Role In Biomedical Field Research Articles

Emerging chemistry in improving the metabolism or degradability of organic/polymeric conjugated materials for biomedical applications

AbstractOrganic/polymeric conjugated materials are playing an increasingly important role in biomedical field. Their special properties such as fluorescence, photosensitization, and photothermal conversion make them promising candidates for disease diagnosis and phototherapy. However, these conjugated materials are usually extremely hydrophobic, so they tend to take a relatively long time to be excreted or metabolized after theranostics, leading to unpredictable side effects, which has made their clinical implementation a daunting task. In this review, we will focus on the safety of organic/polymeric conjugated materials for biomedical applications and discuss in detail the general strategies to improve their metabolism or degradability by rational molecular design, based on representative examples. Finally, the challenges and opportunities are also presented by considering further perspectives.

Novel microbial synthesis of rGO nanosheets for effective photocatalytic remediation of Acid Blue 113 dye, improved seed germination, antimicrobial and antioxidant applications

We report for the first time reduction of graphene oxide (GO) nanosheets (NS) by an isolated bacterium from Lonar lake Bacillus cabrialesii RIRD-SK (MCC 4670). Facile, rapid, ecofriendly, and cost-effective biological approach makes it advantageous over physical and chemical methods. Isolated bacterial strain is deposited in Gene Bank accession number MMZ151886. The physiochemical characterization of rGO NS revealed formation of dark black precipitate within 8 h. UV–Visible spectra of rGO shows absorption peak mainly at 269 nm. Fourier-transform infrared spectroscopy (FTIR) revealed presence of functional biomolecules involved in capping and stabilization of NS. X- ray diffraction (XRD) pattern of rGO confirms pure crystal structure. Scanning electron microscopy (SEM) of rGO showed ultrathin graphene NS morphology having thickness less than 3.5 nm. The elemental composition of graphene oxide (GO) and rGO was studied by energy dispersive spectroscopy (EDS) confirms bacterial reduction GO. Specific surface area rGO about 139.53 m2/g was measured by Brunauer-Emmett-Teller (BET) technique. Raman spectroscopy indicates decrease oxygen containing functional group after bacterial reduction with unique fingerprint of material. The rGO NS showed 90.10 % degradation of Acid Blue 113 diazo dye within 45 min. Bioremediation was confirmed with the help of UV–Visible spectroscopy, thin layer chromatography (TLC), FTIR, High-performance liquid chromatography (HPLC) and Liquid chromatography mass spectroscopy (LCMS). Reduced toxicity of the degraded products was observed by the phytotoxicity experiment. A mechanistic degradation pathway has been proposed. rGO NS also exhibit good antimicrobial and antioxidant properties emphasizing its role in biomedical field.

DNA aptamer functionalized monodisperse Eu/Mn-WH nanoparticle for in vivo magnetic resonance and fluorescence imaging

Because of its biocompatibility, non-immunogenicity, bioactivity, and biodegradability, Whitlockite (WH) plays a crucial role in biomedical fields. However, a layer of oleic acid molecules is attached to the surface of WH synthesized by liquid–solid–solution (LSS) method, which hinders its application in biomedicine field. In this paper, we successfully synthesized hydrophilic nanoparticles with bright red fluorescence and excellent magnetic properties (Eu/Mn-WH-Apt NPs) via the ions doping and ligand exchange strategy. In vitro/vivo experiments show that Eu/Mn-WH-Apt nanoparticles have excellent biocompatibility, dispersion stability, tumor targeting ability, satisfactory fluorescence, and magnetic resonance imaging capabilities. Therefore, the prepared multifunctional Eu/Mn-WH-Apt NPs may provide a new strategy and insights for accurately diagnosing clinical cancer.

On the nature of the thermoresponsiveness of poly(2-isopropyl-2-oxazoline) in aqueous solution

Poly(2-oxazoline)s (POAs) are a class of biocompatible polymers, that is gaining a prominent role in biomedical field due to its thermoresponsiveness at temperatures compatible with physiologically relevant ones. This work represents the first extensive molecular dynamics simulation study of poly(2-isopropyl-2-oxazoline) (PiPOx) - that is amongst the simplest thermoresponsive POAs - both at infinite dilution as well as finite concentration, aimed at unveiling the thermoresponsive nature of this macromolecular class. Benchmarking simulations against experimental data obtained from specifically synthesized PiPOx's with controlled degree of polymerisation, we can explore the nature of thermoresponsive behaviour. This appears to be dominated by intermolecular interactions that lead to the experimentally observed liquid-liquid phase separation (LLPS). By means of a combined atomistic and coarse-grained approach, we could characterise the polymer rich phase formed upon LLPS, finding average properties of the solution, such as the average distance between polymer chains, that are reminiscent of the experimental lattice pitch measured on crystalline phases. At last, we can hint at the presence of a Liquid Crystalline phase in the polymer rich region at high temperatures.

Microfluidic spinning of natural origin microfibers for breast tumor postsurgical treatment

Chinese herb medicines own potential values in breast tumor postsurgical treatment because of their abundant resources and mild health regulating effect; while it is still a challenge to enhance their utilization and effectiveness in breast tumor therapy. Here, we propose novel natural origin microfibers by using microfluidic spinning technology for potential values in breast tumor postsurgical treatment. Premna microphylla (PM), a traditional herbal medicine from natural plant, was chosen as the main component of the microfibers, while curcumin (Cur) with good anti-inflammatory and anti-cancer properties was applied as the encapsulated drug. Due to chemical ion cross-linking in PM, natural origin microfibers could be continuously spun through microfluidics, which would be further woven into a mesh structure. The resultant mesh was endowed with excellent biocompatibility and inhibited properties on breast tumor cell proliferation. By further applied in in vivo experiments, it was demonstrated that the PM microfibers can effectively inhibit the breast tumor recurrence and metastasis after tumor resection surgery. Based on these features, we believe that the natural origin microfibers will broaden the way of postsurgical tumor treatment and play a unique role in biomedical fields.

Microbial Proteases: Potential Tools for Industrial Applications

The use of enzymes in applied biotechnology has progressively increased in both industrial processes, products and in medical field. Proteolytic enzymes play an important regulatory role in many physiological processes and also represent a therapeutic target for several diseases including cancer, hypertension, blood clotting disorders, respiratory and viral infection. Proteases, a largest and ubiquitous class of enzymes, have a divergent role in biomedical field. The current review includes the basic information about the protease classification and optimized growth parameters to maximize the production of alkaline proteases and applications of proteases in a wide variety of industries including leather, textile, food manufacturing, pharmaceutical, detergent and waste management. The review also implicates the importance of genetic tools to obtain the novel engineered protease with improved catalytic performance and stability, pH and thermal tolerance.

Upcycling of Poly(ϵ‐caprolactone) to Valuable Chemicals by TBD‐Catalyzed Efficient Methanolysis Strategy

As a petroleum-derived polyester material, poly(ϵ-caprolactone) (PCL) plays an essential role in biomedical field due to its excellent biocompatibility and non-toxicity. With the increasing use of PCL in recent years, its waste disposal has become a significant challenge. To address this challenge, we demonstrate a high-efficiency organocatalysis strategy for the chemical upcycling of PCL to valuable chemical. Among organocatalysts explored in this article, 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) shows superior performance for transforming end-of-life poly(ϵ-caprolactone) into highly value-added methyl 6-hydroxyhexanoate with quantitative conversion in a short time. The endwise unzipping depolymerization mechanism is corroborated by monitoring molecular weight during depolymerization process and 1 H NMR control experiments. Furthermore, this approach is also practicable for large-scale depolymerization for commercial PCL plastics, providing idea for promoting the sustainable development of PCL plastics.

Biomaterials for microfluidic technology

Abstract Micro/nanomaterial-based drug and cell delivery systems play an important role in biomedical fields for their injectability and targeting. Microfluidics is a rapidly developing technology and has become a robust tool for preparing biomaterial micro/nanocarriers with precise structural control and high reproducibility. By flexibly designing microfluidic channels and manipulating fluid behavior, various forms of biomaterial carriers can be fabricated using microfluidics, including microspheres, nanoparticles and microfibers. In this review, recent advances in biomaterials for designing functional microfluidic vehicles are summarized. We introduce the application of natural materials such as polysaccharides and proteins as well as synthetic polymers in the production of microfluidic carriers. How the material properties determine the manufacture of carriers and the type of cargoes to be encapsulated is highlighted. Furthermore, the current limitations of microfluidic biomaterial carriers and perspectives on its future developments are presented.

Highly Efficient Fluorescent Material Based on Rare-Earth-Modified Polyhydroxyalkanoates.

Fluorescent materials play an important role in biomedical fields. However, the main types of fluorescent materials suffer from several disadvantages especially the biotoxicity, which largely restrict its wider applications in biological fields. In this study, a highly efficient rare-earth-modified fluorescent material was successfully designed and fabricated based on polyhydroxyalkanoates, which are known as biodegradable and biocompatible materials. A new Functional-PHA polymer was microbially synthesized by engineered Halomonas bluephagenesis and was used as a basal matrix to generate the rare-earth-modified PHA. N-Acetyl-l-cysteine-grafted PHA (NAL-grafted-PHA) was first produced via a UV-initiated thiol-ene click reaction and the rare earth metal ions (Eu3+ and Tb3+) were subsequently chelated onto the NAL-grafted-PHA through the coordination effect. The composite material exhibited intense photoluminescence properties under UV laser excitation, indicating the excellent features as fluorescent material. The enhanced hydrophilicity and superior biocompatibility of rare-earth-chelated PHA were confirmed, suggesting its great potential application value in biomedical fields.

Endotoxin removal from human-like collagen by allantoin

ABSTRACTHuman-like collagen(HLC) has an important role in biomedical field, while endotoxin contamination limits it use. In this study, the saturated allantoin as an adsorbent was applied in adsorbing endotoxins from human-like collagen in Tris-acetate-EDTA(TAE) buffer.Finally, the endotoxins carried by allantoin and soluble allantoin could be removed by centrifugation and ultrafiltration. Treated by 400mg/ml of allantoin, at pH6.5 and 25mM NaCl the endotoxins residual in HLC was decreased to 2.38+0.11EU/mg and protein recovery achieved 98.7% in TAE buffer. Endotoxins could be adsorbed on the surface of allantoin crystal by the hydrogen-bond. At pH8.0, the main force was hydrophobic and bivalent bridge between HLC and endotoxins. When the pH was 6.5, the negative-electron repulsion became the main force. And then, Transmission Electron Microscopy(TEM) was used to observe the ultrastruction of HLC,illustrating the protein ultrastruction had not been affected in TAE buffer. In addition, the method of endotoxins removed by allantoin adsorptoin in TAE buffer was safety and greatly reduced the costs,time consumption in contrast with affinity chromatography. As a whole, this paper provided a good idea to establish a large-scale industrial process to remove endotoxin in biomedical field for its simple operation and low cost.

The anti-bacterial poly(caprolactone)-poly(quaternary ammonium salt) as drug delivery carriers.

Anti-bacterial materials play significant role in biomedical field. Researches and applications of new anti-bacterial materials are necessary. Novel linear and star-shaped copolymers of poly(caprolactone)-poly(quaternary ammonium salt) (PCL-PJDMA) were synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. The structures of the copolymers were confirmed by nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy. The copolymers self-assembled into ball-shaped micelles with low critical micelle concentration (10(-4) ∼ 10(-3) mg/ml). An anti-bacterial drug, triclosan, was chosen as a model drug to investigate the potential application of the copolymers in drug-controlled release. The anti-bacterial experiments against Escherichia coli indicated that all the copolymer micelles had anti-bacterial ability and drug-loaded star-shaped PCL-PJDMA micelles were the best. The slow release of the drug from the drug-loaded micelles prolonged anti-bacterial effect. Therefore, PCL-PJDMA themselves have not only anti-bacterial ability but also the copolymer micelles can be used as carriers for anti-bacterial drugs.