Sustained Delivery System Research Articles

On-demand therapeutic delivery of hydrogen sulfide aided by biomolecules.

Hydrogen sulfide (H2S), known as the third gasotransmitter, exerts various physiological functions including cardiac protection, angiogenesis, anti-inflammatory, and anti-cancer capability. Given its promising therapeutic potential as well as severe perniciousness if improper use, the sustained and tunable H2S delivery systems are highly required for H2S-based gas therapy with enhanced bioactivity and reduced side effects. To this end, a series of stimuli-responsive compounds capable of releasing H2S (termed H2S donors) have been designed over the past two decades to mimic the endogenous generation of H2S and elucidate the biological functions. Further to improve the stability of H2S donors and achieve the targeted delivery, various delivery systems have been constructed. In this review, we focus on the recent advances of an emerging subset, biomolecular-based H2S delivery systems, which combine H2S donors with biomolecular vectors including polysaccharide, peptide, and protein. We demonstrated their basic structures, building strategies, and therapeutic applications respectively to unfold their inherent merits endued by biomolecules including biocompatibility, biodegradability as well as expansibility. The varied development potentials of biomolecular-based H2S delivery systems based on their specific properties are also discussed. At the end, brief future outlooks and upcoming challenges are presented as well.

Implementation of a virtual screening service for hydroxychloroquine and chloroquine retinopathy: One‐year results

AbstractPurpose: To evaluate the results of a new virtual screening service for hydroxychloroquine (HQC) and chloroquine (CQ) retinopathy.Methods: Prospective study including patients under long‐term HCQ or CQ therapy referred for screening at a single ophthalmic centre in Portugal over a one‐year period. The virtual clinic consisted of a visit for functional and structural testing, in accordance with the guidelines on HCQ retinopathy screening1,2, followed by a later review by an experienced consultant. Individualized counselling for both patients and prescribing physicians was provided on retinal toxicity risk, safe dosing, and adequate screening intervals.Results: A total of 93 patients under treatment with HCQ attended the virtual clinic. Systemic lupus erythematosus (38.7%) and rheumatoid arthritis (18.3%) were the most prevalent diagnoses. Mean daily HCQ dosing was 5.2 ± 1.6 mg/Kg, with 46.2% patients using a daily dose greater than 5 mg/Kg. Median treatment duration was 48 months (range: 1–264) and 49.5% patients had been treated for longer than 5 years. Renal disease was present in 11 patients (11.8%) and 7 (7.5%) had pre‐existing retinal conditions. Structural changes in macular optical coherence tomography and fundus autofluorescence were rarely detected (3.3%). In contrast, 16 patients (17.2%) presented with abnormal 10‐2 visual field testing. Multifocal electroretinogram was performed in 14 patients (15.1%), detecting characteristic abnormalities of drug toxicity in one patient, with a definite diagnosis of severe HCQ retinopathy. Recommendation for dose adjustment was given in 47.3% of cases, including advice to discontinue HCQ use in 7 (7.5%) patients based on risk factors.Conclusions: Retinal toxicity is a rare adverse effect of HCQ, a therapy increasingly used in the management of autoimmune disorders. Virtual clinics could be a safe and sustainable care delivery system for adequate counselling, risk assessment and early retinopathy detection.References.1. Marmor MF, et al. Recommendations on screening for chloroquine and hydroxychloroquine retinopathy (2016 revision). Ophthalmology 2016; 123:1386–1394.2. Royal College of Ophthalmologists. Hydroxychloroquine and chloroquine retinopathy: recommendations on monitoring. London: Royal College of Ophthalmologists, 2020.

Development of polymeric nanofibers blended with extract of neem (Azadirachta indica), for potential biomedical applications

In recent years, electrospinning has emerged as a promising technique for the preparation of nanofibers with unique properties like flexibility, high porosity and high surface area. In the context of nanodelivery systems, polymer-based nanofibers have become promising carriers of drugs and bioactive compounds ensuring their sustained release and targeted delivery. In this study, neem extract-loaded nanofibers were developed as sustained delivery systems using the electrospinning method. The chitosan, alginate and polyethylene oxide were used as the polymeric matrix for loading of aqueous extract of neem leaves. The prepared nanofibers NF1, NF2 and NF3 carrying 2%, 4% and 6% extract respectively were characterized using SEM, FTIR, XRD and TGA. Further, the as-prepared nanocomposites exhibited a high degree of swelling and dual-phase release of phytoconstituents. Moreover, the developed controlled delivery systems were tested for antifungal and antioxidant potential. Importantly, the bioactivities of the prepared nanofibers could be improved further by using organic extracts which are generally enriched with phytoconstituents. Herein, we selected biodegradable and mucoadhesive biopolymers and an aqueous extract of neem for the development of controlled-delivery nanofibers by electrospinning through a sustainable and cleaner production process. Thus, the prepared biocompatible nanofibrous systems with biphasic release profile could be employed for biomedical applications including wound dressing, soft tissue scaffolds and as transdermal carriers.

Synthesis and characterization of a novel, pH-responsive sustained release nanocarrier using polyethylene glycol, graphene oxide, and natural silk fibroin protein by a green nano emulsification method to enhance cancer treatment

In this study, for the first time, by employing a simple and efficient double nano-emulsification method and using sweet almond oil as the organic phase, polyethylene glycol (PEG)/graphene oxide (GO)/silk fibroin (SF) hydrogel-nanocomposite was synthesized. The aim of the research was to fabricate a biocompatible targeted pH-sensitive sustained release carrier, improve the drug loading capacity and enhance the anticancer effect of doxorubicin (DOX) drug. The obtained values for the entrapment (%EE) and loading efficacy (%LE) were 87.75 ± 0.7 % and 46 ± 1 %, respectively, and these high values were due to the use of GO with a large specific surface area and the electrostatic interaction between the drug and SF. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses confirmed the presence of all the components in the nanocomposite and the suitable interaction between them. Based on the results of dynamic light scattering analysis (DLS) and zeta potential analysis, the mean size of the carrier particles and its surface charge were 293.7 nm and −102.9 mV, respectively. The high negative charge was caused by the presence of hydroxyl groups in GO and SF and it caused proper stability of the nanocomposite. The spherical core-shell structure with its homogeneous surface was also observed in the field emission scanning electron microscopy (FE-SEM) image. The cumulative release percentage of the nanocarrier reached 95.75 after 96 h and it is higher in the acidic environment at all times. The results of fitting the release data to the kinetic models suggested that the mechanism of release was dissolution-controlled anomalous at pH 7.4 and diffusion-controlled anomalous at pH 5.4. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry showed an increase in toxicity on MCF-7 cells and improved apoptotic cell death compared to the free drug. Consequently, the findings of this research introduced and confirmed PEG/GO/SF nanocomposite as an attractive novel drug delivery system for pH-sensitive and sustained delivery of chemotherapeutic agents in biomedicine.

Nanofiber/hydrogel composite scaffold incorporated by silicon nanoparticles for sustained delivery of osteogenic factor: in vitro study

Utilizing bone scaffolds for osteogenic factors delivery has the vital advantage of faster and more efficient tissue regeneration. In this study, rosuvastatin calcium is loaded into the silicon nanoparticles and then incorporated into PLLA nanofibers followed by immersion into the gelatin hydrogel. The fabricated composites are characterized, and a drug release study shows that the nanofibers are the main barrier to drug release and provide sustained release for 21 days. Double encapsulation in the genipin-crosslinked gelatin hydrogel prolonged release to 32 days. The scaffold material shows great potential to provide a sustainable osteogenic factor delivery system.

Correlation between Socio-Economic Characteristics and Housing Quality of Residential Neighbourhoods in Akure, Southwest Nigeria

There is a general paucity of explanations for the emerging social and spatial changes in the pattern and socio-economic traits of urban residential housing units in Nigeria. Hence, this study examined the spatial pattern of residential neighbourhoods; assessed the quality of residential housing units; and evaluated the correlation between the socio-economic position of respondents and housing quality in Akure, Nigeria. Data were derived from the household questionnaire, remotely sensed data (Landsat 8 OLI/TIR, 2021), a Google Earth map, a Street Map of Akure Township, and personal observations. The study adopted a step-wise sampling technique to select 383 samples from 139,069 heads of households in Akure in 2021. Data were analysed using percentage distribution, Pearson Correlation Coefficient, and t-test. Results indicated varying housing qualities across three residential zones in Akure, Nigeria; houses in the low-density residential areas were of better quality than the other residential zones. The quality of houses occupied was influenced by the type of occupation, level of education and average annual income of residents. The study concluded that inadequate housing facilities are fundamental to the observed deteriorating housing qualities in the study area. Therefore, the study suggested improvement of the existing infrastructures and the provision of new ones in the study area. The main contribution of this study is to proffer solutions for a sustainable housing delivery system to facilitate a better quality of life in Nigerian urban centres.

Self-Healing Thermosensitive Hydrogel for Sustained Release of Dexamethasone for Ocular Therapy.

The aim of this study was to develop an injectable hydrogel delivery system for sustained ocular delivery of dexamethasone. To this end, a self-healing hydrogel consisting of a thermosensitive ABA triblock copolymer was designed. The drug was covalently linked to the polymer by copolymerization of methacrylated dexamethasone with N-isopropylacrylamide (NIPAM) and N-acryloxysuccinimide (NAS) through reversible addition-fragmentation chain transfer (RAFT) polymerization, using poly(ethylene glycol) (PEG) functionalized at both ends with a chain transfer agent (CTA). Hydrogel formation was achieved by mixing aqueous solutions of the formed thermosensitive polymer (with a cloud point of 23 °C) with cystamine at 37 °C, to result in covalent cross-linking due to the reaction of the N-hydroxysuccimide (NHS) functionality of the polymer and the primary amines of cystamine. Rheological analysis showed both thermogelation and covalent cross-linking at 37 °C, as well as the self-healing properties of the formed network, which was attributed to the presence of disulfide bonds in the cystamine cross-links, making the system injectable. The release of dexamethasone from the hydrogel occurred through ester hydrolysis following first-order kinetics in an aqueous medium at pH 7.4 over 430 days at 37 °C. Based on simulations, administration of 100 mg of hydrogel would be sufficient for maintaining therapeutic levels of dexamethasone in the vitreous for at least 500 days. Importantly, dexamethasone was released from the hydrogel in its native form as determined by LC-MS analysis. Cytocompatibility studies showed that at clinically relevant concentrations, both the polymer and the cross-linker were well tolerated by adult retinal pigment epithelium (ARPE-19) cells. Moreover, the hydrogel did not show any toxicity to ARPE-19 cells. The injectability of the hydrogel, together with the long-lasting release of dexamethasone and good cytocompatibility with a retinal cell line, makes this delivery system an attractive candidate for treatment of ocular inflammatory diseases.

Modeling of the effect of cerebrospinal fluid flow modulation on locally delivered drugs in the brain.

Cerebrospinal fluid (CSF) plays a vital role in maintaining brain homeostasis and recent research has focused on elucidating the role that convective flow of CSF plays in brain health. This paper describes a computational compartmental model of how CSF dynamics affect drug pharmacokinetics in the rat brain. Our model implements a local, sustained release approach for drug delivery to the brain. Simulation outputs highlight the potential for modulating CSF flow to improve overall drug pharmacokinetics in the central nervous system and suggest that concomitant CSF modulation and optimized drug release rates from implantable depots can be used to engineer the duration of action of chemotherapeutics. As an example, the tissue exposure of temozolomide, the standard of care treatment for glioblastoma, was modeled in conjunction with two CSF-modulating drugs: acetazolamide and verapamil. Simulations indicate that temozolomide exposure in the interstitial fluid is increased by 25% when using local sustained release delivery systems and concomitant acetazolamide delivery to reduce CSF production. This computational model can be used to produce insight on how to appropriately modulate CSF production and engineer drug release to tailor drug exposure in the brain while limiting off-target effects. As new research continues to elucidate the dynamic roles of CSF, this model can be further improved and leveraged to provide information on how CSF modulation may play a beneficial role in treating a wide variety of neurological disease.

PH-sensitive self-assembled nanofibers based on electrostatic interaction and Schiff base bonding for controlled release of curcumin

In this study, chitosan-dialdehyde-β-cyclodextrin-curcumin (CS-DCD-CUR) and alginate dialdehyde (ADA) were alternately deposited on the surface of electrospun cellulose acetate (CA) nanofibers driven by Schiff base bonding and electrostatic attraction. With the increasing number of bilayers, the self-assembled nanofibers showed an increased average fiber diameter from 441 to 576 nm and had relatively rough surfaces. The improved thermal stability and tensile strength of self-assembled nanofibers were attributed to the interactions between CS-DCD-CUR and ADA. The self-assembled nanofibers exhibited pH-sensitive release characteristics under acidic conditions due to the weakening of the electrostatic interaction and the hydrolysis of Schiff-base. Moreover, the self-assembled nanofibers could be used for sustained and controlled release of the curcumin within 620 min and maintained the antioxidant activities. The highest radical scavenging activities against ABTS and DPPH radicals of the nanofibers were 24.75% and 83.56%, respectively. These results suggested that the layer-by-layer self-assembled nanofibers provided a pH-responsive sustained delivery system for bioactive substances with potential applications in functional foods. • Electrostaic attraction and Schiff base bonding were employed to drive the self-assembly of the nanofibers. • The self-assembled nanofibers had improved thermal stability and mechanical properties. • The self-assembled nanofibers exhibited a controllable pH-sensitive release manner of curcumin.

Tethered drug release from model contact lenses

AbstractDrug delivery to the eye remains a challenge due to low compliance and high amounts of drug loss resulting from anatomical barriers. Contact lens‐based delivery systems offer many advantages since their increased corneal residence time can increase drug bioavailability. A releasable, sustained delivery system from a contact lens has been evaluated in the current work. Using a labile lactide spacer, comprised of poly(ethylene glycol) methacrylate, varying numbers of lactide units and succinic anhydride, a model drug, R‐roscovitine, was covalently incorporated into model silicone lenses (consisting of 80 mol% N,N‐dimethylacrylamide and 20 mol% of a modified silicone). This enabled a greater amount of the drug to remain in the material following extraction with isopropyl alcohol, a common purification procedure used in lens manufacturing. The incorporation of the tether and drug did not substantially alter the bulk properties of the materials, with their water content remaining between 32% and 36% and their transmittance remaining at over 90% at 600 nm. Drug release from these materials exceeded 2 weeks, with the longer lactide tethers showing greater release as expected. This demonstrates that these covalently modified materials have the potential to be used to deliver drugs in a sustained manner. © 2022 Society of Industrial Chemistry.

Effects of Microencapsulated Ferulic Acid or Its Prodrug Methyl Ferulate on Neuroinflammation Induced by Muramyl Dipeptide.

Ferulic acid (Fer) is known for its antioxidant and anti-inflammatory activities, which are possibly useful against neurodegenerative diseases. Despite the ability of Fer to permeate the brain, its fast elimination from the body does not allow its therapeutic use to be optimized. The present study proposes the preparation and characterization of tristearin- or stearic acid-based solid lipid microparticles (SLMs) as sustained delivery and targeting systems for Fer. The microparticles were produced by conventional hot emulsion techniques. The synthesis of the methyl ester of Fer (Fer-Me) allowed its encapsulation in the SLMs to increase. Fer-Me was hydrolyzed to Fer in rat whole blood and liver homogenate, evidencing its prodrug behavior. Furthermore, Fer-Me displayed antioxidant and anti-inflammatory properties. The amount of encapsulated Fer-Me was 0.719 ± 0.005% or 1.507 ± 0.014% in tristearin or stearic acid SLMs, respectively. The tristearin SLMs were able to control the prodrug release, while the stearic acid SLMs induced a significant increase of its dissolution rate in water. Jointly, the present results suggest that the tristearin SLMs loaded with Fer-Me could be a potential formulation against peripheral neuropathic pain; conversely, the stearic acid SLMs could be useful for Fer-Me uptake in the brain after nasal administration of the formulation.

Imatinib Mesylate-Loaded Rosin/Cinnamon Oil-Based In Situ Forming Gel against Colorectal Cancer Cells.

Localized delivery systems have been typically designed to enhance drug concentration at a target site and minimize systemic drug toxicity. A rosin/cinnamon oil (CO) in situ forming gel (ISG) was developed for the sustainable delivery of imatinib mesylate (IM) against colorectal cancer cells. CO has been claimed to express a potent anticancer effect against various cancer cells, as well as a synergistic effect with IM on colorectal cancer cells; however, poor aqueous solubility limits its application. The effect of rosin with the adding CO was assessed on physicochemical properties and in vitro drug release from developed IM-loaded rosin/CO-based ISG. Moreover, in vitro cytotoxicity tests were conducted against two colorectal cancer cells. All formulations exhibited Newtonian flow behavior with viscosity less than 266.9 cP with easier injectability. The adding of CO decreased the hardness and increased the adhesive force of the obtained rosin gel. The gel formation increased over time under microscopic observation. CO-added ISG had a particle-like gel appearance, and it promoted a higher release of IM over a period of 28 days. All tested ISG formulations revealed cytotoxicity against HCT-116 and HT-29 cell lines at different incubation times. Thus, CO-loaded rosin-based ISG can act as a potentially sustainable IM delivery system for chemotherapy against colorectal cancer cells.

Mobile health in China: Does it meet availability, accessibility, acceptability and quality standards?

ObjectiveThe objective of this article is to evaluate mobile health practices under China's health care system through the lens of the right to health framework and to offer directions for policy improvement. MethodThe theoretical framework of this article is made up of four essential elements of the right to health, namely availability, accessibility, acceptability and quality of health care. This approach has been applied by a broad range of stakeholders to assess national health programmes. In addition, a review was conducted of literature published between 2015 and 2019 to determine the service categories of mHealth. ResultsThe findings show that mobile health has been used in a wide range of practices for health care and well-being management. The assessment of mHealth practices under the AAAQ framework suggests that mobile health contributes to accessibility and efficiency and health promotion. However, some shortcomings are also identified. ConclusionsTo achieve sustainability of mHealth in the health care system and realise its potential, this evaluation points out four aspects of policy improvement. An integrated approach, a robust governance mechanism, a new legislative response and private sector engagement are required. Public interest summaryThe vibrant growth of mobile health has prompted an emerging need of integrating it to a sustainable service delivery system for achieving universal health coverage. To remove barriers for the implementation of mobile health nationwide, it is necessary to assess mobile health practices in the Chinese health care system as a whole. This article provides an evaluation of mobile health in China under the right to health framework (availability, accessibility, affordability and quality). It suggests that mobile health brings positive results but also unintended consequences, both for individuals and the health care system. Therefore, we point out that the integrated solution, the governance mechanism, the relevant legislation and private sector engagement should be further addressed in mobile health policy. The findings presented in this article indicate the current status and policy considerations for navigating the future direction of mobile health.

Potential Combinatory Effect of Cannabidiol and Triclosan Incorporated into Sustained Release Delivery System against Oral Candidiasis.

Candida albicans is a common fungal pathogen. Biofilm formation on various surfaces is an important determinant of C. albicans pathogenicity. Our previous results demonstrated the high potential of cannabidiol (CBD) to affect C. albicans biofilms. Based on these data, we investigated the possibility of incorporating CBD and/or triclosan (an antimicrobial agent that is widely utilized in dentistry) in a sustained-release varnish (SRV) (SRV-CBD, SRV-triclosan) to increase their pharmaceutical potential against C. albicans biofilm, as well as that of the mixture of the agents into SRV (SRV-CBD/triclosan). The study was conducted in a plastic model, on agar, and in an ex vivo tooth model. Our results demonstrated strong antibiofilm activity of SRV-CBD and SRV-triclosan against C. albicans in all tested models. Both formulations were able to inhibit biofilm formation and to remove mature fungal biofilm. In addition, SRV-CBD and SRV-triclosan altered C. albicans morphology. Finally, we observed a dramatic enhancement of antibiofilm activity when combined SRV-CBD/triclosan was applied. In conclusion, we propose that incorporation of CBD or triclosan into SRV is an effective strategy to fight fungal biofilms. Importantly, the data demonstrate that our CBD/triclosan varnish is safe, and is not cytotoxic for normal mammalian cells. Furthermore, we propose that CBD and triclosan being in mixture in SRV exhibit complementary antibiofilm activity, and thus can be explored for further development as a potential treatment against fungal infections.

Sustained drug delivery strategies for treatment of common substance use disorders: Promises and challenges.

Substance use disorders (SUDs) are a leading cause of death and other ill health effects in the United States and other countries in the world. Several approaches ranging from detoxification, behavioral therapy, and the use of antagonists or drugs with counter effects are currently being applied for its management. Amongst these, drug therapy is the mainstay for some drug abuse incidences, as is in place specifically for opioid abuse or alcohol dependence. The severity of the havocs observed with the SUDs has triggered constant interest in the discovery and development of novel medications as well as suitable or most appropriate methods for the delivery of these agents. The chronic need of such drugs in users warrants the need for their prolonged or sustained systemic availability. Further, the need to improve patient tolerance to medication, limit invasive drug use and overall treatment outcome are pertinent considerations for embracing sustained release designs for medications used in managing SUDs. This review aims to provide an overview on up-to-date advances made with regards to sustained delivery systems for the drugs for treatment of different types of SUDs such as opioid, alcohol, tobacco, cocaine, and cannabis use disorders. The clinical relevance, promises and the limitations of deployed sustained release approaches along with future opportunities are discussed.

Intravesical sustained release system of lidocaine and oxybutynin results from in vitro and animal study.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic debilitating condition of unknown etiology. Intravesical lidocaine demonstrated pain relief in patients with IC/BPS. Intravesical oxybutynin has shown therapeutic efficacy in patients with urinary bladder disorders. However, loss of drug with urination requiring multiple administrations and immediate dilution of drug concentration by residual urine in the bladder mitigated intravesical use of both drugs in clinical practice. The aim of this study was to evaluate the efficacy and safety of fixed-dose combination of lidocaine and oxybutynin, forming in the urine a sustained delivery system named TRG-042. In-vitro, we have quantitatively tested the concentration of lidocaine and oxybutynin released from TRG-042 in artificial urine. Following the successful in-vitro study weekly formulation of TRG-042 was instilled intravesically to six pigs. All pigs were followed with cystoscopy to assess the gradual degradation of the delivery system and to evaluate bladder response over 7 days. Daily blood samples were tested for drug quantization. In-vitro studies have demonstrated oxybutynin and lidocaine sustained release over 1-week period coupled with full degradation of the matrix. None of the animals demonstrated any side effects following instillation. Cystoscopy examination observed gradual disintegration of TRG-042 over 1-week with no adverse reaction to the mucosa. Plasma concentrations of oxybutynin and lidocaine were uniformly stable over the 1-week period [1.46 ± 0.176ng/ml and 4.29 ± 2.48ng/ml respectively(mean ± SEM)] with almost undetectable concentration of N-desethyloxybutynin (NDO)[0.032 ± 0.068ng/ml]. The in-vitro and animal data demonstrated that TRG-042 can safely be used for intravesical sustained release of lidocaine and oxybutynin in the treatment of BPS/IC.

Folate-conjugated liposome as effective Drug delivery system for Quercetin

Active ingredient (AI), particularly quercetin (Q), has been known as types of nature-derived chemotherapic agents in cancer treatment. However, the advantages of this agent concerning antineoplastic activity were restricted by its poor water solubility. Therefore, the encapsulation of AI in nano-mediated drug delivery is expected to create diverse effects and can sufficiently increase their therapeutic outcomes. The aim of this present study was to effectively prepare folate-conjugated liposome (L-F) that can enhance the delivery of Q. L-F containing Q (Q-L-F) was successfully prepared by thin film technique, using tween 80-ethylenediamine-acid folic as the surface-modified moiety. Physicochemical parameters, including morphology, particles size, zeta potential, drug encapsulation efficiency and release profiles were investigated. In addition, in vitro cytotoxicity of the prepared formulation was evaluated against NCI-H460 cell line. Results showed that the prepared Q-L-F had a mean size of about 166.8 nm with low polydispersity index (below 0.5) and high encapsulation efficiency (96.6%). The release profile showed a sustained release of Q up to 48 h. Moreover, Q-L-F liposomal system was proposed to have the enhanced toxicity effect toward cancerous cells with expressed folate receptors due to the targeting of folic acid conjugated. In support for this, cell proliferation using SRB assay on NCI-H460 cells demonstrated that Q-L-F exhibited higher cytotoxicity than quercetin loaded conventional liposome (Q-L). For the purpose of researching, the data could serve as proof for the potential of L-F as a sustained delivery system for Q in anti-cancer therapy.

Towards innervation of bioengineered muscle constructs: Development of a sustained neurotrophic factor delivery and release system

Surgical implantation of biomanufactured skeletal muscle constructs has recently emerged as a promising strategy to treat volumetric muscle defects. However, due to the slow rate of neural regeneration and integration, timely innervation of the implanted constructs with the host peripheral nerves remains an unresolved challenge. This study aims to develop a sustained release neurotrophic factor (NF) delivery system to accelerate peripheral nerve regeneration and innervation of three-dimensional (3D) bioprinted skeletal muscle constructs. Poly (lactic-co-glycolic acid) (PLGA) microspheres were selected as a delivery system for efficient loading and sustained release of two potent NFs: ciliary neurotrophic factor (CNTF) and glial cell line-derived neurotrophic factor (GDNF). We demonstrate that the NFs can be loaded within the PLGA microspheres with a high encapsulation efficiency (75.4% ± 12.6%). The NF-loaded microspheres were incorporated into the fibrinogen-based bioink used to produce biomanufactured skeletal muscle constructs and tested for printability. The microspheres did not change the viscoelastic properties of the bioink, nor did they affect the viability of human muscle progenitor cells. The release kinetic test confirmed that the bioprinted muscle constructs with the NFs-loaded microspheres released the NFs in a sustained manner compared to the bioprinted muscle construct without microspheres. The released NFs maintained their biological activities. In an in vitro neurite outgrowth assay, the NFs released from the PLGA microspheres facilitated the neurite growth over a longer time scale than the NFs directly loaded in the hydrogel. These results demonstrate the feasibility of incorporating the microsphere-based NF delivery system for accelerating neural regeneration in future in vivo applications involving biomanufactured muscle constructs.

Development of stimuli-responsive chitosan based hydrogels with anticancer efficacy, enhanced antibacterial characteristics, and applications for controlled release of benzocaine

In this work, chitosan and poly(vinylpyrrolidone) based (3-mercaptopropyl)trimethoxysilane (MPTMS) crosslinked hydrogels were prepared for application in drug delivery systems. The swelling behavior in distilled water started to increase until the crosslinker concentration reached the optimum level. The most significant swelling characteristic is noticed in buffer solutions, with higher swelling in an acidic medium and lower swelling in a neutral or basic medium. Morphological studies showed the porous and network structure of specimens, which determines the swelling and release characteristics. Hydrogels manifested antimicrobial characteristics against Listeria monocytogenes (L. monocytogenes) and Salmonella typhimurium (S. typhimurium) bacterial strains. The cell viability against RAW 264.7 cell lines was >90%, and at higher concentrations, the hydrogels showed anti-cancer efficacy against stomach cancerous AGS cell lines. In vitro drug release analysis of benzocaine in phosphate buffer saline (pH 7.4) and simulated intestinal fluid (pH 6.8) showed >90% release within 2 h. These stimuli-responsive hydrogels show enhanced antimicrobial characteristics, biocompatibility, and anti-cancer efficacy, as well as capability of drug release in a controlled manner, which makes them remarkable candidates for use in sustainable drug delivery systems.

Preparation and Use of Cellular Reagents: A Low-resource Molecular Biology Reagent Platform.

Protein reagents are indispensable for most molecular and synthetic biology procedures. Most conventional protocols rely on highly purified protein reagents that require considerable expertise, time, and infrastructure to produce. In consequence, most proteins are acquired from commercial sources, reagent expense is often high, and accessibility may be hampered by shipping delays, customs barriers, geopolitical constraints, and the need for a constant cold chain. Such limitations to the widespread availability of protein reagents, in turn, limit the expansion and adoption of molecular biology methods in research, education, and technology development and application. Here, we describe protocols for producing a low-resource and locally sustainable reagent delivery system, termed "cellular reagents," in which bacteria engineered to overexpress proteins of interest are dried and can then be used directly as reagent packets in numerous molecular biology reactions, without the need for protein purification or a constant cold chain. As an example of their application, we describe the execution of polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) using cellular reagents, detailing how to replace pure protein reagents with optimal amounts of rehydrated cellular reagents. We additionally describe a do-it-yourself fluorescence visualization device for using these cellular reagents in common molecular biology applications. The methods presented in this article can be used for low-cost, on-site production of commonly used molecular biology reagents (including DNA and RNA polymerases, reverse transcriptases, and ligases) with minimal instrumentation and expertise, and without the need for protein purification. Consequently, these methods should generally make molecular biology reagents more affordable and accessible. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Preparation of cellular reagents Alternate Protocol 1: Preparation of lyophilized cellular reagents Alternate Protocol 2: Evaluation of bacterial culture growth via comparison to McFarland turbidity standards Support Protocol 1: SDS-PAGE for protein expression analysis of cellular reagents Basic Protocol 2: Using Taq DNA polymerase cellular reagents for PCR Basic Protocol 3: Using Br512 DNA polymerase cellular reagents for loop-mediated isothermal amplification (LAMP) Support Protocol 2: Building a fluorescence visualization device.