Glucose-Responsive Trehalose Hydrogel for Insulin Stabilization and Delivery

Trehalose-based coacervates for local bioactive protein delivery to the central nervous system

Therapeutic outcomes of local biomolecule delivery to the central nervous system (CNS) using bulk biomaterials are limited by inadequate drug loading, neuropil disruption, and severe foreign body responses. Effective CNS delivery requires addressing these issues and developing well-tolerated, highly-loaded carriers that are dispersible within local neural parenchyma. Here, we synthesized biodegradable trehalose-based polyelectrolyte oligomers using facile A2:B3:AR thiol-ene Michael addition reactions that form complex coacervates upon mixing of oppositely charged oligomers. Coacervates permit high concentration loading and controlled release of bioactive growth factors, enzymes, and antibodies, with modular formulation parameters that confer tunable release kinetics. Coacervates are cytocompatible with cultured neural cells in vitro and can be formulated to either direct intracellular protein delivery or sequester media containing proteins and remain extracellular. Coacervates serve as effective vehicles for precisely delivering biomolecules, including bioactive neurotrophins, to the mouse striatum following intraparenchymal injection. These results support the use of trehalose-based coacervates as part of therapeutic protein delivery strategies for CNS disorders.

A Biomineralized Bifunctional Patient-Friendly Nanosystem for Sustained Glucose Monitoring and Control in Diabetes

Regular blood glucose monitoring and control is necessary for people with type 1 or advanced type 2 diabetes, yet diagnosing and treating patients with diabetes in an accurate, sustained and patient-friendly manner remains limited. Here, a glucose-responsive bifunctional nanosystem (PGOxMns) is constructed via one-pot biomineralisation of manganese dioxide with glucose oxidase and ε-poly-L-lysine. Under hyperglycaemic conditions, the cascade reactions that occur when glucose interacts with PGOxMns can trigger the production of Mn(II), which enhances the magnetic resonance imaging signal. Simultaneously, manganese dioxide catalyses the decomposition of toxic hydrogen peroxide into oxygen, which also maintains glucose oxidase (GOx) activity. In an in vivo model of diabetes, PGOxMns is used to monitor glucose levels (0-20 mm) and allowed identification of diabetic mice via T1-weighted MRI. Furthermore, PGOxMns is found to have a high insulin-loading capacity (83.6%), likely due to its positive charge. A single subcutaneous injection of insulin-loaded nanosystem (Ins-PGOxMns) into diabetic mice resulted in a rapid and efficient response to a glucose challenge and prolonged blood glucose level control (< 200 mg dL-1) for up to 50 h. Overall, this proof-of-concept study demonstrates the feasibility of using biomineralised nanosystems to develop patient-friendly strategies for glucose monitoring and control.

Glucose-Responsive Microgel Comprising Conventional Insulin and Curcumin-Laden Nanoparticles: a Potential Combination for Diabetes Management

Successful management of type 2 diabetes mellitus (T2DM), a complex and chronic disease, requires a combination of anti-hyperglycemic and anti-inflammatory agents. Here, we have conceptualized and tested an integrated "closed-loop mimic" in the form of a glucose-responsive microgel (GRM) based on chitosan, comprising conventional insulin (INS) and curcumin-laden nanoparticles (nCUR) as a potential strategy for effective management of the disease. In addition to mimicking the normal, on-demand INS secretion, such delivery systems display an uninterrupted release of nCUR to combat the inflammation, oxidative stress, lipid metabolic abnormality, and endothelial dysfunction components of T2DM. Additives such as gum arabic (GA) led to a fivefold increased INS loading capacity compared to GRM without GA. The GRMs showed excellent in vitro on-demand INS release, while a constant nCUR release is observed irrespective of glucose concentrations. Thus, this study demonstrates a promising drug delivery technology that can simultaneously, and at physiological/pathophysiological relevance, deliver two drugs of distinct physicochemical attributes in the same formulation.

Glucose-Responsive Chitosan Nanoparticle/Poly(vinyl alcohol) Hydrogels for Sustained Insulin Release In Vivo

Stimuli-responsive hydrogels (HGs) with a controlled drug release profile are the current challenge for advanced therapeutic applications. Specifically, antidiabetic drug-loaded glucose-responsive HGs are being investigated for closed-loop insulin delivery in insulin-dependent diabetes patients. In this direction, new design principles must be exploited to create inexpensive, naturally occurring, biocompatible glucose-responsive HG materials for the future. In this work, we developed chitosan nanoparticle/poly(vinyl alcohol) (PVA) hybrid HGs (CPHGs) for controlled insulin delivery for diabetes management. In this design, PVA and chitosan nanoparticles (CNPs) are cross-linked with a glucose-responsive formylphenylboronic acid (FPBA)-based cross-linker in situ. Leveraging the structural diversity of FPBA and its pinacol ester-based cross-linkers, we fabricate six CPHGs (CPHG1-6) with more than 80% water content. Using dynamic rheological measurements, we demonstrate elastic solid-like properties of CPHG1-6, which are dramatically reduced under low-pH and high-glucose environments. An in vitro drug release assay reveals size-dependent glucose-responsive drug release from the CPHGs under physiological conditions. It is important to note that the CPHGs show appreciable self-healing and noncytotoxic properties. Promisingly, we observe a significantly slower insulin release profile from the CPHG matrix in the type-1 diabetes (T1D) rat model. We are actively pursuing scaling up of CPHGs and the in vivo safety studies for clinical trial in the near future.

A new boronate ester-based crosslinking strategy allows the design of nonswelling and long-term stable dynamic covalent hydrogels

Dynamic hydrogels are viscoelastic materials that can be designed to be self-healing, malleable, and injectable, making them particularly interesting for a variety of biomedical applications. To design dynamic hydrogels, dynamic covalent crosslinking reactions are attracting increasing attention. However, dynamic covalent hydrogels tend to swell, and often lack stability. Boronate ester-based hydrogels, which result from the dynamic covalent reaction between a phenylboronic acid (PBA) derivative and a diol, are based on stable precursors, and can therefore address these limitations. Yet, boronate ester formation hardly occurs at physiological pH. To produce dynamic covalent hydrogels at physiological pH, we performed a molecular screening of PBA derivatives in association with a variety of diols, using hyaluronic acid as a polymer of interest. The combination of Wulff-type PBA (wPBA) and glucamine stood out as a unique couple to obtain the desired hydrogels. We showed that optimized wPBA/glucamine hydrogels are minimally- to non-swelling, stable long term (over months), tunable in terms of mechanical properties, and cytocompatible. We further characterized their viscoelastic and self-healing properties, highlighting their potential for biomedical applications.

Stimuli-Responsive Boron-Based Materials in Drug Delivery

Drug delivery systems, which use components at the nanoscale level as diagnostic tools or to release therapeutic drugs to particular target areas in a regulated manner, are a fast-evolving field of science. The active pharmaceutical substance can be released via the drug delivery system to produce the desired therapeutic effect. The poor bioavailability and irregular plasma drug levels of conventional drug delivery systems (tablets, capsules, syrups, etc.) prevent them from achieving sustained delivery. The entire therapy process may be ineffective without a reliable delivery system. To achieve optimal safety and effectiveness, the drug must also be administered at a precision-controlled rate and the targeted spot. The issues with traditional drug delivery are overcome by the development of stimuli-responsive controlled drug release. Over the past decades, regulated drug delivery has evolved considerably, progressing from large- and nanoscale to smart-controlled drug delivery for several diseases. The current review provides an updated overview of recent developments in the field of stimuli-responsive boron-based materials in drug delivery for various diseases. Boron-containing compounds such as boron nitride, boronic acid, and boron dipyrromethene have been developed as a moving field of research in drug delivery. Due to their ability to achieve precise control over drug release through the response to particular stimuli (pH, light, glutathione, glucose or temperature), stimuli-responsive nanoscale drug delivery systems are attracting a lot of attention. The potential of developing their capabilities to a wide range of nanoscale systems, such as nanoparticles, nanosheets/nanospheres, nanotubes, nanocarriers, microneedles, nanocapsules, hydrogel, nanoassembly, etc., is also addressed and examined. This review also provides overall design principles to include stimuli-responsive boron nanomaterial-based drug delivery systems, which might inspire new concepts and applications.

Dual-Drug Conjugated Glyco-Nanoassemblies for Tumor-Triggered Targeting and Synergistic Cancer Therapy

Drug-conjugated nanoassemblies potentiate the efficiency of anticancer drugs through the advantages of high drug-loading capacity and passive/active targeting ability in cancer therapy. This study describes the synthesis of gemcitabine (Gem) and cisplatin (cisPt) dual-drug-functionalized glyco-nanoassemblies (GNs) for anticancer drug delivery systems. It also investigates the pH-triggered drug delivery of the conventional anticancer drug cisPt. A Gem-functionalized well-defined glycoblock copolymer backbone (P(iprFruMA-b-MAc)-Gem), which consists of fructose and methacrylic acid segments, was synthesized via a reversible addition-fragmentation chain transfer (RAFT) polymerization method. Following the hydrolysis of the protecting groups on the backbone copolymer, cisPt functionalization of P(FruMA-b-MAc)-Gem in aqueous media was carried out during the transformation of glycoblock polymers into self-assembled spherical glyco-nanoassemblies (GN3). Monodrug-functionalized glyco-nanoassemblies were also prepared either with Gem (GN1) or cisPt (GN2) to compare the synergetic effect of dual-drug conjugated glyco-nanoassemblies (GN3). The sizes of glyco-nanoassemblies GN1, GN2, and GN3 were found as 5.76 ± 0.64, 59.80 ± 0.13, and 53.80 ± 3.90 nm and dispersity (Đ) values as 0.476, 0.292, and 0.311 by dynamic light scattering (DLS) measurement, respectively. The in vitro studies revealed that the drug-free glyco-nanoassemblies are biocompatible at concentrations higher than 296 μg/mL. The drug-conjugated glyco-nanoassemblies (GN1 and GN2) exhibited in vitro cytotoxicity against human breast cancer cell lines of MDA-MB-231 comparable to free Gem and cisPt, illustrating an efficient drug release into the tumor environment. Additionally, GNs exhibited higher selectivity and preferential cellular internalization in MDA-MB-231 when compared to healthy cell lines of CCD-1079Sk. These dual-drug conjugated GNs can effectively enhance the killing of cancer cells and increase synergistic chemotherapy.

Recent Advances in Smart Hydrogels Prepared by Ionizing Radiation Technology for Biomedical Applications

Materials with excellent biocompatibility and targeting can be widely used in the biomedical field. Hydrogels are an excellent biomedical material, which are similar to living tissue and cannot affect the metabolic process of living organisms. Moreover, the three-dimensional network structure of hydrogel is conducive to the storage and slow release of drugs. Compared to the traditional hydrogel preparation technologies, ionizing radiation technology has high efficiency, is green, and has environmental protection. This technology can easily adjust mechanical properties, swelling, and so on. This review provides a classification of hydrogels and different preparation methods and highlights the advantages of ionizing radiation technology in smart hydrogels used for biomedical applications.

Bottom-up design of hydrogels for programmable drug release

Hydrogels are a promising drug delivery system for biomedical applications due to their biocompatibility and similarity to native tissue. Programming the release rate from hydrogels is critical to ensure release of desired dosage over specified durations, particularly with the advent of more complicated medical regimens such as combinatorial drug therapy. While it is known how hydrogel structure affects release, the parameters that can be explicitly controlled to modulate release ab initio could be useful for hydrogel design. In this review, we first survey common physical models of hydrogel release. We then extensively go through the various input parameters that we can exercise direct control over, at the levels of synthesis, formulation, fabrication and environment. We also illustrate some examples where hydrogels can be programmed with the input parameters for temporally and spatially defined release. Finally, we discuss the exciting potential and challenges for programming release, and potential implications with the advent of machine learning.

Study protocol for a pilot randomised controlled trial evaluating the effectiveness of oral trehalose on inflammatory factors, oxidative stress, nutritional and clinical status in traumatic head injury patients receiving enteral nutrition

INTRODUCTION

In traumatic brain injury (TBI) patients, inflammatory processes and oxidative stress have been linked to the development of neurodegenerative diseases, disability, increased rate of muscle catabolism, malnutrition, hospital stay and mortality. Previous in vitro and in vivo studies have shown that trehalose can decrease inflammatory and oxidative factors. Therefore, the present study was designed to evaluate the effect of oral trehalose consumption on this marker in critically ill TBI patients at intensive care unit (ICU).

METHODS AND ANALYSIS

This study is a pilot randomised, prospective and double-blind clinical trial. The study sample size is of 20 (10 patients in each group) TBI patients aged 18-65 years at ICU. Randomisation is performed by permuted block randomisation method. The allocation ratio is 1:1. An intervention group will receive 30 g of trehalose instead, as a part of the carbohydrate of daily bolus enteral feeding and the control group will receive standard isocaloric hospital bolus enteral feeding for 12 days. The inflammatory factors (C reactive protein, interleukin 6) and oxidative stress markers (glutathione, malondialdehyde, superoxide dismutase, pro-oxidant-antioxidant balance, total antioxidant capacity) will be measured at the baseline, at the 6th day, and at the end of the study (12th day). Sequential Organ Failure Assessment, Acute Physiology and Chronic Health Evaluation II, Nutrition Risk in the Critically ill scores, 28-day mortality, anthropometric assessments and the clinical and nutritional status will be measured. Each patient's nutritional needs will be calculated individually. The statistical analysis would be based on the intention to treat.

ETHICS AND DISSEMINATION

The vice-chancellor of the research centre of Mashhad University of Medical Sciences is sponsoring this study. IR.MUMS.MEDICAL.REC.1400.113.

TRIAL REGISTRATION NUMBER

Iranian Registry of Clinical Trials (IRCT) Id: IRCT20210508051223N1, Registration date: 26 July 2021.

Poly(trehalose methacrylate) as an Excipient for Insulin Stabilization: Mechanism and Safety

Insulin, the oldest U.S. Food and Drug Administration (FDA)-approved recombinant protein and a World Health Organization (WHO) essential medicine for treating diabetes globally, faces challenges due to its storage instability. One approach to stabilize insulin is the addition of poly(trehalose methacrylate) (pTrMA) as an excipient. The polymer increases the stability of the peptide to heat and mechanical agitation and has a low viscosity suitable for injection and pumps. However, the safety and stabilizing mechanism of pTrMA is not yet known and is required to understand the potential suitability of pTrMA as an insulin excipient. Herein is reported the immune response, biodistribution, and insulin plasma lifetime in mice, as well as investigation into insulin stabilization. pTrMA alone or formulated with ovalbumin did not elicit an antibody response over 3 weeks in mice, and there was no observable cytokine production in response to pTrMA. Micropositron emission tomography/microcomputer tomography of ⁶⁴Cu-labeled pTrMA showed excretion of 78-79% ID/cc within 24 h and minimal liver accumulation at 6-8% ID/cc when studied out to 120 h. Further, the plasma lifetime of insulin in mice was not altered by added pTrMA. Formulating insulin with 2 mol equiv of pTrMA improved the stability of insulin to standard storage conditions: 46 weeks at 4 °C yielded 87.0% intact insulin with pTrMA present as compared to 7.8% intact insulin without the polymer. The mechanism by which pTrMA-stabilized insulin was revealed to be a combination of inhibiting deamidation of amino acid residues and preventing fibrillation, followed by aggregation of inactive and immunogenic amyloids all without complexing insulin into its hexameric state, which could delay the onset of insulin activity. Based on the data reported here, we suggest that pTrMA stabilizes insulin as an excipient without adverse effects in vivo and is promising to investigate further for the safe formulation of insulin.

Recent Advances in Glucose Responsive Insulin Delivery Systems: Novel Hydrogels and Future Applications

Over the past several decades, there have been major advancements in the field of glucose sensing and insulin delivery for the treatment of type I diabetes mellitus. The introduction of closed-loop insulin delivery systems that deliver insulin in response to specific levels of glucose in the blood has shifted significantly the research in this field. These systems consist of encapsulated glucose-sensitive components such as glucose oxidase or phenylboronic acid in hydrogels, microgels or nanoparticles. Since our previous evaluation of these systems in a contribution in 2004, new systems have been developed. Important improvements in key issues, such as consistent insulin delivery over an extended period of time have been addressed. In this contribution, we discuss recent advancements over the last 5 years and present persisting issues in these technologies that must be overcome in order for these systems to be applicable in patients.

Synthesis and Application of Trehalose Materials

Trehalose is a naturally occurring, nonreducing disaccharide that is widely used in the biopharmaceutical, food, and cosmetic industries due to its stabilizing and cryoprotective properties. Over the years, scientists have developed methodologies to synthesize linear polymers with trehalose units either in the polymer backbone or as pendant groups. These macromolecules provide unique properties and characteristics, which often outperform trehalose itself. Additionally, numerous reports have focused on the synthesis and formulation of materials based on trehalose, such as nanoparticles, hydrogels, and thermoset networks. Among many applications, these polymers and materials have been used as protein stabilizers, as gene delivery systems, and to prevent amyloid aggregate formation. In this Perspective, recent developments in the synthesis and application of trehalose-based linear polymers, hydrogels, and nanomaterials are discussed, with a focus on utilization in the biomedical field.

Silk fibroin hydrogel containing Sesbania sesban L. extract for rheumatoid arthritis treatment

Purpose

Rheumatoid arthritis, a chronic and progressive inflammation condition in the joints, has significantly reduced the patient quality of life and life expectancy. Crucially, there is no complete therapy for this disease, and the current treatments possess numerous side effects. Thus, novel therapeutic approach is necessary. To that end, this study developed novel silk fibroin in-situ hydrogel containing Sesbania sesban L. extract, a plant with high anti-inflammatory actions that are beneficial for rheumatoid arthritis treatments.

Methods

The hydrogels were manufactured using simple method of spontaneous gelation at different temperature. The gel properties of morphology, gelation time, viscosity, gel strength, stability, drug loading capacity, drug release rate, and in-vitro anti-inflammatory activity were investigated with appropriate methods.

Results

The optimal formulation had highly porous structure, with a gelation time of 0.5 h at room temperature and bodily temperature of 37 °C, a viscosity of 2530 ± 50 cP, a gel strength of 1880.14 ± 35.10 g, and a physical stability of >6 months. Moreover, the hydrogel contained the Sesbania sesban L. leaf extract with a total phenolic content of 92.8 ± 8.30 mg GAE/g, and sustained the release rate for >20 dạys, followed the Higuchi model. Regarding the in-vitro activities, all formulations were nontoxic to the RAW 264.7 cell line and demonstrated comparable anti-inflammatory activity to the free extract, in terms of the NO reduction levels.

Conclusion

Conclusively, the systems possessed potential properties to be further investigated to become a prospective rheumatoid arthritis treatment.

Connecting the Dynamics and Reactivity of Arylboronic Acids to Emergent and Stimuli-Responsive Material Properties

Over the past two decades, arylboronic acid-functionalized biomaterials have been used in a variety of sensing and stimuli-responsive scaffolds. Their diverse applications result from the diverse reactivity of arylboronic acids,...

Repurposing Pinacol Esters of Boronic Acids for Tuning Viscoelastic Properties of Glucose-responsive Polymer Hydrogels: Effects on Insulin Release Kinetics

In the era of the diabetes pandemic, Injectable hydrogels (HGs) capable of releasing the desired amount of insulin under hyperglycemic conditions will significantly advance smart insulin development. Several smart boronic...

Structurally analogous trehalose and sucrose glycopolymers – comparative characterization and evaluation of their effects on insulin fibrillation

Comprehensive comparative characterization of highly structurally similar, RAFT-prepared trehalose and sucrose glycopolymers.

Advanced Hydrogels for the Controlled Delivery of Insulin

Insulin is a peptide hormone that is key to regulating physiological glucose levels. Its molecular size and susceptibility to conformational change under physiological pH make it challenging to orally administer insulin in diabetes. The most effective route for insulin delivery remains daily injection. Unfortunately, this results in poor patient compliance and increasing the risk of micro- and macro-vascular complications and thus rising morbidity and mortality rates in diabetics. The use of 3D hydrogels has been used with much interest for various biomedical applications. Hydrogels can mimic the extracellular matrix (ECM) and retain large quantities of water with tunable properties, which renders them suitable for administering a wide range of sensitive therapeutics. Several studies have demonstrated the fixation of insulin within the structural mesh of hydrogels as a bio-scaffold for the controlled delivery of insulin. This review provides a concise incursion into recent developments for the safe and effective controlled delivery of insulin using advanced hydrogel platforms with a special focus on sustained release injectable formulations. Various hydrogel platforms in terms of their methods of synthesis, properties, and unique features such as stimuli responsiveness for the treatment of Type 1 diabetes mellitus are critically appraised. Key criteria for classifying hydrogels are also outlined together with future trends in the field.

Enhancement of bioactivity, thermal stability and tumor retention by self-fused concatenation of green fluorescent protein

The widespread application of protein and peptide therapeutics is hampered by their poor stability, strong immunogenicity and short half-life. However, the existing protein modification technologies require the introduction of exogenous macromolecules, resulting in inevitable immunogenicity and decreased bioactivity. Herein, we reported an easy but universal protein modification approach, self-fused concatenation (SEC), to enhance the in vitro thermal stability and in vivo tumor retention of proteins. In this proof of concept study, we successfully obtained a set of green fluorescence protein (GFP) concatemers, monomer (GFP 1), dimer (GFP 2) and trimer (GFP 3) of GFP, and systematically studied the effects of SEC on the biological activity and stability of GFP. Notably, GFP concatemers displayed remarkable improvement in in vitro bioactivity and thermal stability over the monomeric GFP. In a murine tumor model, GFP 2 and GFP 3 exhibited significantly prolonged duration, with increases of 220- and 381-fold relative to GFP 1 in tumor retention 4 h after administration. Furthermore, the biological activity, thermal stability and tumor retention can be enhanced by the concatenated number of self-fused proteins. These findings demonstrate that SEC may be a promising alternative to design advanced protein and peptide therapeutics with enhanced pharmaceutic profiles.

The Core-Shell Structure, Not Sugar, Drives the Thermal Stabilization of Single-Enzyme Nanoparticles

Trehalose is widely assumed to be the most effective sugar for protein stabilization, but exactly how unique the structure is and the mechanism by which it works are still debated. Herein, we use a polyion complex micelle approach to control the position of trehalose relative to the surface of glucose oxidase within cross-linked and non-cross-linked single-enzyme nanoparticles (SENs). The distribution and density of trehalose molecules in the shell can be tuned by changing the structure of the underlying polymer, poly(N-[3-(dimethylamino)propyl] acrylamide (PDMAPA). SENs in which the trehalose is replaced with sucrose and acrylamide are prepared as well for comparison. Isothermal titration calorimetry, dynamic light scattering, and asymmetric flow field-flow fraction in combination with multiangle light scattering reveal that two to six polymers bind to the enzyme. Binding either trehalose or sucrose close to the enzyme surface has very little effect on the thermal stability of the enzyme. By contrast, encapsulation of the enzyme within a cross-linked polymer shell significantly enhances its thermal stability and increases the unfolding temperature from 70.3 °C to 84.8 °C. Further improvements (up to 92.8 °C) can be seen when trehalose is built into this shell. Our data indicate that the structural confinement of the enzyme is a far more important driver in its thermal stability than the location of any sugar.

Self-Assembled, Dilution-Responsive Hydrogels for Enhanced Thermal Stability of Insulin Biopharmaceuticals

Biotherapeutics currently dominate the landscape of new drugs because of their exceptional potency and selectivity. Yet, the intricate molecular structures that give rise to these beneficial qualities also render them unstable in formulation. Hydrogels have shown potential as stabilizing excipients for biotherapeutic drugs, providing protection against harsh thermal conditions experienced during distribution and storage. In this work, we report the utilization of a cellulose-based supramolecular hydrogel formed from polymer–nanoparticle (PNP) interactions to encapsulate and stabilize insulin, an important biotherapeutic used widely to treat diabetes. Encapsulation of insulin in these hydrogels prevents insulin aggregation and maintains insulin bioactivity through stressed aging conditions of elevated temperature and continuous agitation for over 28 days. Further, insulin can be easily recovered by dilution of these hydrogels for administration at the point of care. This supramolecular hydrogel system shows promise as a stabilizing excipient to reduce the cold chain dependence of insulin and other biotherapeutics.

Enhancing the stability of adalimumab by engineering additional glycosylation motifs

Monoclonal antibodies (mAbs) are of high value in the diagnostic and treatment of many debilitating diseases such as cancers, auto-immune disorders and infections. Unfortunately, protein aggregation is one of the ongoing challenges, limiting the development and application of mAbs as therapeutic products by decreasing half-life, increasing immunogenicity and reducing activity. We engineered an aggregation-prone region of adalimumab, the top selling mAb product worldwide - with additional glycosylation sites to enhance its resistance to aggregation by steric hindrance as a next generation biologic. We found that the addition of N-glycans in the Fab domain significantly enhanced its conformational stability, with some variants increasing the melting temperature of the Fab domain by >6 °C. The mutations tested had minimal impact on antigen binding affinity, or affinity to Fcγ receptors responsible for effector function. Our findings highlight the significant utility of this rational engineering approach for enhancing the conformational stability of therapeutic mAbs and other next-generation antibody formats.

Modular Fabrication of Intelligent Material-Tissue Interfaces for Bioinspired and Biomimetic Devices

One of the goals of biomaterials science is to reverse engineer aspects of human and nonhuman physiology. Similar to the body's regulatory mechanisms, such devices must transduce changes in the physiological environment or the presence of an external stimulus into a detectable or therapeutic response. This review is a comprehensive evaluation and critical analysis of the design and fabrication of environmentally responsive cell-material constructs for bioinspired machinery and biomimetic devices. In a bottom-up analysis, we begin by reviewing fundamental principles that explain materials' responses to chemical gradients, biomarkers, electromagnetic fields, light, and temperature. Strategies for fabricating highly ordered assemblies of material components at the nano to macro-scales via directed assembly, lithography, 3D printing and 4D printing are also presented. We conclude with an account of contemporary material-tissue interfaces within bioinspired and biomimetic devices for peptide delivery, cancer theranostics, biomonitoring, neuroprosthetics, soft robotics, and biological machines.

Stimuli-Responsive Drug Release from Smart Polymers

Over the past 10 years, stimuli-responsive polymeric biomaterials have emerged as effective systems for the delivery of therapeutics. Persistent with ongoing efforts to minimize adverse effects, stimuli-responsive biomaterials are designed to release in response to either chemical, physical, or biological triggers. The stimuli-responsiveness of smart biomaterials may improve spatiotemporal specificity of release. The material design may be used to tailor smart polymers to release a drug when particular stimuli are present. Smart biomaterials may use internal or external stimuli as triggering mechanisms. Internal stimuli-responsive smart biomaterials include those that respond to specific enzymes or changes in microenvironment pH; external stimuli can consist of electromagnetic, light, or acoustic energy; with some smart biomaterials responding to multiple stimuli. This review looks at current and evolving stimuli-responsive polymeric biomaterials in their proposed applications.