Polymers For Biomedical Applications Research Articles

Structural Engineering of l-Aspartic Amphiphilic Polyesters for Enzyme-Responsive Drug Delivery and Bioimaging in Cancer Cells.

Design and development of amphiphilic polyesters based on bioresources are very important to cater to the ever-growing need for biodegradable polymers in biomedical applications. Here, we report structural engineering of enzyme-responsive amphiphilic polyesters based on l-amino acid bioresources and study their drug delivery aspects in the cancer cell line. For this purpose, an l-aspartic acid-based polyester platform is chosen, and two noncovalent forces such as hydrogen bonding and side-chain hydrophobic interactions are introduced to study their effect on the aqueous self-assembly of nanoparticles. The synthetic strategy involves the development of l-aspartic acid-based dimethyl ester monomers with acetal and stearate side chains and subjecting them to solvent-free melt polycondensation reactions to produce side-chain-functionalized polyesters in the entire composition range. Postpolymerization acid catalyst deprotection of acetal yielded hydroxyl-functionalized polyesters. Amphiphilicity of the polymer is carefully fine-tuned by varying the composition of the stearate and hydroxyl units in the polymer chains to produce self-assembly in water. Various drugs such as camptothecin (CPT), curcumin (CUR), and doxorubicin (DOX) and biomarkers like 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS), rose bengal (RB), and Nile red (NR) are successfully encapsulated in the polymer nanoparticles. Cytotoxicity of biodegradable polymer nanoparticles is tested in normal and breast cancer cell lines. The polymer nanoparticles are found to be highly biocompatible and delivered the anticancer drugs in the intracellular compartments of the cells.

Fabrication of Antimicrobial Hydrogel Using Biodegradable Blended Materials for Skin Applications

Biodegradable polymers are very useful polymers in biomedical applications. In this research, several hydrogels were fabricated by using two polymers, Polyvinyl alcohol (PVA) and Chitosan (Chs) by the solvent casting method in order to use them for skin applications. Several tests were carried out on these membranes such as Agar diffusion method to examine their antimicrobial activities, Fourier transform infrared microscopy (FTIR) test to study the differences in their chemical structures. Uniaxial tensile test was performed to examine the mechanical characteristics of these membranes. In addition, the wettability test was used to investigate the hydrophobicity or hydrophilicity of the surfaces. The results showed that all membranes are hydrophilic, of which the contact angles are less than 90°. The membrane manufactured from 75:25 Chs-PVA is more hydrophobic (contact angle is 74°) than other membranes made of 50:50 Chs-PVA and 25:75 Chs-PVA as the contact angles were 59° and 61°, respectively. The tensile test results indicate that the membrane fabricated of the PVA and the membrane that was fabricated by 75% Chs and 25% PVA has the highest tensile strength of 17.9 MPa, 16.2 MPa and Young^’ s Modulus of 181.2 MPa and 7.18 MPa, respectively. The highest strain at break was observed by the membrane of 25:75 Chs-PVA which equals to 24.67%. Chitosan membranes showed inhibition zones of about 2.99 cm and 2.75 cm in length, and 75:25 Chs-PVA membranes showed 5.1 and 5.91 cm in length for E.coli. To sum up, this copolymer is considered as promising hydrogel for skin applications such as wound dressing.

The Importance of AI Algorithm Combined with Tunable LCST Smart Polymers in Biomedical Applications

Smart polymers, also known as stimulus-responsive polymers or environmentally sensitive polymers, are a class of polymers that exhibit changes in their physical and chemical properties in response to various external stimuli, including small physical and chemical changes in the environment. These stimuli can trigger changes in the properties of the smart polymer, such as phase, shape, optics, mechanics, electric field, surface energy, reaction rate, permeability, and perception. Due to the biological sluggishness of conventional smart polymers, different manifestations of polymers are realized through the combination of AI technologies, including water solubility, adsorption on the surface of the carrier, or part of the cross-linked polymer system. While the definition of smart polymers can include two-phase transition processes such as glass transition and melting, the focus of research in the field of smart polymer systems is their behavior in polymer aqueous solutions, interfaces, and hydrogels. In this paper, a noteworthy smart polymer Low critical solution temperature (LCST) polymer is analyzed based on the combination of AI algorithm and deep learning. By carefully designing and modifying the structure of the polymer, the researchers can adjust the LCST to approximate the physiological temperature, making it suitable for potential biomedical applications. Looking ahead, an important development direction is the creation of LCST-type polymers that exhibit a variety of responses to different stimuli, while also improving their biodegradability. Incorporating AI into the design and modification of these polymers could facilitate the development of advanced smart materials with enhanced properties and functionality, opening up new possibilities in areas such as biotechnology, drug delivery, and response materials.

Renewable Polymers in Biomedical Applications: From the Bench to the Market

Renewable Polymers in Biomedical Applications: From the Bench to the Market

Biodegradable Polymers in Biomedical Applications: A Review—Developments, Perspectives and Future Challenges

Biodegradable polymers are materials that, thanks to their remarkable properties, are widely understood to be suitable for use in scientific fields such as tissue engineering and materials engineering. Due to the alarming increase in the number of diagnosed diseases and conditions, polymers are of great interest in biomedical applications especially. The use of biodegradable polymers in biomedicine is constantly expanding. The application of new techniques or the improvement of existing ones makes it possible to produce materials with desired properties, such as mechanical strength, controlled degradation time and rate and antibacterial and antimicrobial properties. In addition, these materials can take virtually unlimited shapes as a result of appropriate design. This is additionally desirable when it is necessary to develop new structures that support or restore the proper functioning of systems in the body.

Rational design of hyper‐crosslinked polymers for biomedical applications

AbstractHyper‐crosslinked polymers (HCPs) are a family of polymers that possess several desirable characteristics, including high specific surface area, excellent stability, tunable porous structures, and low‐cost reagents. As a result, HCPs have gained significant attention in the areas of gas storage, adsorption, catalysis, separation, and carbon precursors, exhibiting advanced performances in catalytic and energy‐related applications. Recently, researchers have explored the potential of HCPs in biomedical engineering. In this review, we discuss classical synthesis strategies and morphological assembly methods used to create HCPs with unique biological properties. We also highlight the latest advances in emerging biomedical areas of HCPs, such as drug delivery, antimicrobial, bioimaging, and biosensing. By providing various examples, we further discuss the correlations between the structures, morphologies, and enhanced biomedical properties of the HCPs. Finally, we summarize the key applications of HCPs and provide an outlook on the research direction to encourage further development of biomedically available HCPs. Overall, HCPs offer promising potential as a new class of materials for use in biomedical applications, and continued research in this field will lead to exciting discoveries and breakthroughs.

International Polymer Characterization Conference (POLY‐CHAR [Halle|Siegen] 2022)

The International Polymer Characterization Conference POLY-CHAR [Halle│Siegen] 2022 took place as a live digital event from 22nd to 25th May 2022. Organized jointly by the Fraunhofer IMWS in Halle, Germany, and the Institute of Physical Chemistry I of the University of Siegen, Germany, the IUPAC (International Union of Pure and Applied Chemistry)-endorsed conference brought together more than 100 participants from five continents, who shared their research findings ranging from theoretical to experimental and fundamental to applied aspects of polymers. As a a nonprofit, non-governmental organization POLY-CHAR is devoted to creating a friendly interdisciplinary environment to share information, organize student exchange and cooperation, to hold international meetings and to provide a platform for scientist from all over the word. The annual POLY-CHAR conferences are not limited to mere “POLYmer CHARacterization”. Instead, POLY-CHAR offers an open platform for sharing ideas, presenting results, meeting old and making new friends in the scientific community. Topics cover a wide area in synthesis, characterization, modification and application of polymeric materials and composites, probably best summarized under the terms “Advanced Materials' and ‘Functional Materials”. The live digital format chosen for POLY-CHAR [Halle│Siegen] 2022 enabled unrestricted worldwide participation in times of global uncertainty regarding travel restrictions due to the COVID-19 pandemic. On the first day of the conference the POLY-CHAR Short Course was held. The topics of the lectures presented on the subsequent days by 5 plenary speakers, 24 invited speakers, 66 oral speakers, 9 poster presenters from 28 countries included (i) polymer synthesis, (ii) polymer characterization, (iii) polymer physics, theory and simulations, (iv) circular economy of polymers and sustainable applications, (v) polymers for biomedical applications, biopolymers, biomedical materials and biotechnology, (vi) biopolymers in nutrition and health, (vii) elastomers, amorphous materials, nanomaterials and smart materials, (viii) mechanics of polymers, and (ix) adhesives, coatings, and advanced hybrid materials. In addition to several POLY-CHAR and IUPAC prizes for outstanding oral presentations and posters of young scientists, the following prestigious prizes were awarded to well renowned scientists to honor their academic achievements: The Richard Robert Ernst Award went to Prof. Dr. Jianyong Jin (The University of Auckland, New Zealand), the Jean-Marie Lehn Award went to Prof. Dr. Zheng Li (Peking University, China) and the Pierre-Gilles de Gennes Award was awarded to José Luis Gómez Ribelles (Universitat Polìtècnica de València, Spain). This conference volume represents a focused selection of contributions from different areas of polymer and materials science. The next conference in the series, POLY-CHAR [Auckland] 2023, will be held in presence in Auckland, New Zealand, from January 22nd to 26th, 2023. This meeting will be co-hosted by Prof. Jianyong Jin and Prof. Duncan McGillvray. Sven Henning, Fraunhofer IMWS, Germany Ralf Lach, Institut für Polymerwerkstoffe e.V. (IPW), Germany Holger Schönherr, University of Siegen, Germany

Intrinsically Disordered Synthetic Polymers in Biomedical Applications.

In biology and medicine, intrinsically disordered synthetic polymers bio-mimicking intrinsically disordered proteins, which lack stable three-dimensional structures, possess high structural/conformational flexibility. They are prone to self-organization and can be extremely useful in various biomedical applications. Among such applications, intrinsically disordered synthetic polymers can have potential usage in drug delivery, organ transplantation, artificial organ design, and immune compatibility. The designing of new syntheses and characterization mechanisms is currently required to provide the lacking intrinsically disordered synthetic polymers for biomedical applications bio-mimicked using intrinsically disordered proteins. Here, we present our strategies for designing intrinsically disordered synthetic polymers for biomedical applications based on bio-mimicking intrinsically disordered proteins.

Preparation and Surface Characterization of Chitosan-Based Coatings for PET Materials.

Poly(ethylene terephthalate)-PET-is one of the most frequently used polymers in biomedical applications. Due to chemical inertness, PET surface modification is necessary to gain specific properties, making the polymer biocompatible. The aim of this paper is to characterize the multi-component films containing chitosan (Ch), phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), immunosuppressant cyclosporine A (CsA) and/or antioxidant lauryl gallate (LG) which can be utilized as a very attractive material for developing the PET coatings. Chitosan was employed owing to its antibacterial activity and also its ability to promote cell adhesion and proliferation favorable for tissue engineering and regeneration purposes. Moreover, the Ch film can be additionally modified with other substances of biological importance (DOPC, CsA and LG). The layers of varying compositions were prepared using the Langmuir-Blodgett (LB) technique on the air plasma-activated PET support. Then their nanostructure, molecular distribution, surface chemistry and wettability were determined by atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), contact angle (CA) measurements and the surface free energy and its components' determination, respectively. The obtained results show clearly the dependence of the surface properties of the films on the molar ratio of components and allow for a better understanding of the coating organization and mechanisms of interactions at the molecular level both inside the films and between the films and the polar/apolar liquids imitating the environment of different properties. The organized layers of this type can be helpful in gaining control over the surface properties of the biomaterial, thus getting rid of the limitations in favor of increased biocompatibility. This is a good basis for further investigations on the correlation of the immune system response to the presence of biomaterial and its physicochemical properties.

Roles of aqueous nonsolvents influencing the dynamic stability of poly-(n-butyl methacrylate) thin films at biologically relevant temperatures.

Poly-(n-butyl methacrylate) (PnBMA) is an important polymer in biomedical applications. Here we study the stability of PnBMA thin films prepared on top of slippery silicon substrates and exposed to nonsolvent aqueous incubation media like water and phosphate-buffered saline (PBS) at temperatures relevant to biological applications (37 °C, 25 °C and 4 °C). Dewetting hole growth experiments allowed us to probe the instability in PnBMA films upon incubation followed by thermal annealing. From the early stage of dewetting hole growth dynamics, we inferred that the stability of the thin PnBMA films decreases as a function of the duration and temperature of incubation, even though the films were found not to readily dewet at room temperature after incubation. It is also observed that water incubation makes films more unstable than incubation in PBS. We explained our observations as a combined effect of (i) an increase in surface energy of the PnBMA film due to incubation, (ii) an increased destabilizing effect due to the dominant polar interactions between the incubation medium and the PnBMA film and (iii) the plasticization effect of PnBMA films by the incubation media. Plasticization resulted in a decrease in the modulus of PnBMA thin films as a function of incubation time. The viscosity of PnBMA films upon incubation was found to be coupled to the decreasing modulus. Thus we infer that incubation in common aqueous nonsolvents can detrimentally affect the stability of polymers limiting their specific usages through a complex interplay of multiple molecular level phenomena.

New Opportunities for Organic Semiconducting Polymers in Biomedical Applications

The life expectancy of humans has been significantly elevated due to advancements in medical knowledge and skills over the past few decades. Although a lot of knowledge and skills are disseminated to the general public, electronic devices that quantitatively diagnose one’s own body condition still require specialized semiconductor devices which are huge and not portable. In this regard, semiconductor materials that are lightweight and have low power consumption and high performance should be developed with low cost for mass production. Organic semiconductors are one of the promising materials in biomedical applications due to their functionalities, solution-processability and excellent mechanical properties in terms of flexibility. In this review, we discuss organic semiconductor materials that are widely utilized in biomedical devices. Some advantageous and unique properties of organic semiconductors compared to inorganic semiconductors are reviewed. By critically assessing the fabrication process and device structures in organic-based biomedical devices, the potential merits and future aspects of the organic biomedical devices are pinpointed compared to inorganic devices.

Hyaluronic Acid-Based Nanomaterials as a New Approach to the Treatment and Prevention of Bacterial Infections.

Bacterial contamination of medical devices is a great concern for public health and an increasing risk for hospital-acquired infections. The ongoing increase in antibiotic-resistant bacterial strains highlights the urgent need to find new effective alternatives to antibiotics. Hyaluronic acid (HA) is a valuable polymer in biomedical applications, partly due to its bactericidal effects on different platforms such as contact lenses, cleaning solutions, wound dressings, cosmetic formulations, etc. Because the pure form of HA is rapidly hydrolyzed, nanotechnology-based approaches have been investigated to improve its clinical utility. Moreover, a combination of HA with other bactericidal molecules could improve the antibacterial effects on drug-resistant bacterial strains, and improve the management of hard-to-heal wound infections. This review summarizes the structure, production, and properties of HA, and its various platforms as a carrier in drug delivery. Herein, we discuss recent works on numerous types of HA-based nanoparticles to overcome the limitations of traditional antibiotics in the treatment of bacterial infections. Advances in the fabrication of controlled release of antimicrobial agents from HA-based nanosystems can allow the complete eradication of pathogenic microorganisms.

Recent advances of chitosan-based polymers in biomedical applications and environmental protection

Interest in polymer-based biomaterials such as chitosan and its modifications and also the methods of their application in various fields of science is uninterruptedly growing. Owing to unique physicochemical, biological, ecological, physiological properties, such as biocompatibility, biodegradability, stability in the natural environment, non-toxicity, high biological activity, economic affordability, chelating of metal ions, high sorption properties, chitosan is used in various biomedical and industrial processes. The reactivity of the amino and hydroxyl groups in the structure makes it more interesting for diverse applications in drug delivery, tissue engineering, wound healing, regenerative medicine, blood anticoagulation and bone, tendon or blood vessel engineering, dentistry, biotechnology, biosensing, cosmetics, water treatment, agriculture. Taking into account the current situation in the world with COVID-19 and other viruses, chitosan is also active in the form of a vaccine system, it can deliver antibodies to the nasal mucosa and load gene drugs that prevent or disrupt the replication of viral DNA/RNA, and deliver them to infected cells. The presented article is an overview of the nowaday state of the application of chitosan, based on literature of recent years, showing importance of fundamental and applied studies aimed to expand application of chitosan-based polymers in many fields of science.

Biological study of polyethyleneimine functionalized polycaprolactone 3D‐printed scaffolds for bone tissue engineering

AbstractPolycaprolactone (PCL) is one of the most usable polymers in biomedical applications. Despite this, PCL has a natural hydrophobic character and a lack of active site for interaction with other materials. For overcome this limitation, surface modification using polyethyleneimine (PEI) was carried out to provide suitable hydrophilic surface for cell adhesion and proliferation. The 3D printed scaffolds were analyzed by scanning electron microscopy (SEM), attenuated total reflection‐Fourier transform‐infrared (ATR‐FTIR) spectroscopy, contact angle, and ninhydrin assay. Finally, enzymatic degradation behavior and cellular activities were carried out to investigate the possible application in bone tissue engineering. The results indicated the formation of uniform PEI coating along with increase in the surface hydrophilicity through absorption of 43% of free amine groups, improvement of enzymatic degradation of PCL scaffolds about four times from 1.51% to 5.77% after 4 days. Also, the biological studies indicated that modification of PCL scaffolds surface with PEI provided a suitable platform for attachment, differentiation and proliferation of MC3T3 cells in the PCL‐based scaffolds. Taken together, the results suggest that the 3D composite scaffolds could be used in bone tissue engineering.

Implementation of Water-Soluble Cyclodextrin-Based Polymers in Biomedical Applications: How Far Are We?

Cyclodextrin-based polymers can be prepared starting from the naturally occurring monomers following green and low-cost procedures. They can be selectively derivatized pre- or post-polymerization allowing to fine-tune functionalities of ad hoc customized polymers. Preparation nowadays has reached the 100g scale thanks also to the interest of industries in these extremely versatile compounds. During the last 15 years, these macromolecules have been the object of intense investigations in view of possible biomedical applications as the ultimate goal and large amounts of scientific data are now available. Compared to their monomeric models, already used in the formulation of various therapeutic agents, they display superior behavior in terms of their solubility in water and solubilizing power toward drugs incompatible with biological fluids. Moreover, they allow the combination of more than one type of therapeutic agent in the polymeric system. In this review, a complete state of the art on the knowledge and potentialities of water-soluble cyclodextrin-based polymers as therapeutic agents as well as carrier systems for different types of therapeutics to implement combination therapy is provided. Finally, a perspective on their assets for innovation in disease treatment as well as their limits that still need to be addressed is given.

Blood Compatibility of Hydrophilic Polyphosphoesters.

Polyphosphoesters (PPEs) are a class of versatile degradable polymers. Despite the high potential of this class of polymers in biomedical applications, little is known about their blood interaction and compatibility. We evaluated the hemocompatibility of water-soluble PPEs (with different hydrophilicities and molar masses) and PPE-coated model nanocarriers. Overall, we identified high hemocompatibility of PPEs, comparable to poly(ethylene glycol) (PEG), currently used for many applications in nanomedicine. Hydrophilic PPEs caused no significant changes in blood coagulation, negligible platelet activation, the absence of red blood cells lysis, or aggregation. However, when a more hydrophobic copolymer was studied, some changes in the whole blood clot strength at the highest concentration were detected, but only concentrations above that are typically used for biomedical applications. Also, the PPE-coated model nanocarriers showed high hemocompatibility. These results contribute to defining hydrophilic PPEs as a promising platform for degradable and biocompatible materials in the biomedical field.

A mini review on centrifugal spinning technique for production of nanofibers and its applications in drug delivery

Nanofibers possess distinctive physicochemical and biological properties and have been utilized in a wide range of research and commercial applications. Electrospinning is a widely used technology for generating nanofibers, but due to its low production rate, it lacks scalability. Centrifugal spinning is a low-cost process for producing nanofibers that is simple, quick, and scalable. It has emerged as a potential technology for fabricating nanofibers with a variety of applications due to its extremely high production rate and multifaceted features. The centrifugal spinning process involves injecting the polymer solution or melt in a rotating spinneret. When the spinning head reaches a critical speed, the centrifugal force overcomes the surface tension of the spinning liquid, and a liquid jet ejects from the nozzle tip. The jet is then stretched further, resulting in solidified nanofibers on the collector. The technique is capable of producing 3D nanofiber scaffolds from various polymers for biomedical applications. This paper describes in details the centrifugal spinning process, its classification, principle and applications of the centrifugal spun nano/micro fibers in drug delivery and wound dressing. Keywords: Nanofibers, Centrifugal spinning, Solubility enhancement, drug delivery.

Polymers for Biomedical Applications: The Importance of Hydrophobicity in Directing Biological Interactions and Application Efficacy

The past decades have seen significant research effort in the field of polymers for a range of biomedical applications, driven by the promising prospect of these materials for realizing next generation therapeutics in the clinic. In this regard, it is widely accepted that polymer properties such as chemistry, charge, and block composition, as well as properties of their self-assemblies including size, shape, surface chemistry, and biodegradation, all influence and direct their interactions with cells and biological membranes. In particular, polymer hydrophobicity is a property of interest, with growing evidence demonstrating the significant impact that hydrophobic interactions with lipid membranes and proteins can have on biomaterial application efficacy within the body. However, to date, this phenomenon has been relatively underexplored, and therefore there exists no clear universal understanding to direct polymer design. In this Perspective, we highlight important contributions to this field, focusing on seminal studies which investigate experimentally and theoretically how incorporation of hydrophobic moieties within polymer systems can influence their ultimate properties when used in biomedical applications. In this way, we aim to signify future directions in the design of highly performing polymers for biomedicine, making a case for the importance of standardized computational modeling to achieve widely applicable conclusions and facilitate future translational efforts.

Modulation of Crystallinity through Radiofrequency Electromagnetic Fields in PLLA/Magnetic Nanoparticles Composites: A Proof of Concept.

To modulate the properties of degradable implants from outside of the human body represents a major challenge in the field of biomaterials. Polylactic acid is one of the most used polymers in biomedical applications, but it tends to lose its mechanical properties too quickly during degradation. In the present study, a way to reinforce poly-L lactic acid (PLLA) with magnetic nanoparticles (MNPs) that have the capacity to heat under radiofrequency electromagnetic fields (EMF) is proposed. As mechanical and degradation properties are related to the crystallinity of PLLA, the aim of the work was to explore the possibility of modifying the structure of the polymer through the heating of the reinforcing MNPs by EMF within the biological limit range f·H < 5·× 109 Am−1·s−1. Composites were prepared by dispersing MNPs under sonication in a solution of PLLA. The heat released by the MNPs was monitored by an infrared camera and changes in the polymer were analyzed with differential scanning calorimetry and nanoindentation techniques. The crystallinity, hardness, and elastic modulus of nanocomposites increase with EMF treatment.

Principles for Controlling the Shape Recovery and Degradation Behavior of Biodegradable Shape-Memory Polymers in Biomedical Applications.

Polymers with the shape memory effect possess tremendous potential for application in diverse fields, including aerospace, textiles, robotics, and biomedicine, because of their mechanical properties (softness and flexibility) and chemical tunability. Biodegradable shape memory polymers (BSMPs) have unique benefits of long-term biocompatibility and formation of zero-waste byproducts as the final degradable products are resorbed or absorbed via metabolism or enzyme digestion processes. In addition to their application toward the prevention of biofilm formation or internal tissue damage caused by permanent implant materials and the subsequent need for secondary surgery, which causes secondary infections and complications, BSMPs have been highlighted for minimally invasive medical applications. The properties of BSMPs, including high tunability, thermomechanical properties, shape memory performance, and degradation rate, can be achieved by controlling the combination and content of the comonomer and crystallinity. In addition, the biodegradable chemistry and kinetics of BSMPs, which can be controlled by combining several biodegradable polymers with different hydrolysis chemistry products, such as anhydrides, esters, and carbonates, strongly affect the hydrolytic activity and erosion property. A wide range of applications including self-expending stents, wound closure, drug release systems, and tissue repair, suggests that the BSMPs can be applied as actuators on the basis of their shape recovery and degradation ability.