Weifeng Lin

Bio: Weifeng Lin is an academic researcher from Weizmann Institute of Science. The author has contributed to research in topics: Protein adsorption & Medicine. The author has an hindex of 21, co-authored 46 publications receiving 1219 citations. Previous affiliations of Weifeng Lin include Zhejiang University.

Investigation of the hydration of nonfouling material poly(sulfobetaine methacrylate) by low-field nuclear magnetic resonance

Abstract: The strong surface hydration layer of nonfouling materials plays a key role in their resistance to nonspecific protein adsorption. Poly(sulfobetaine methacrylate) (polySBMA) is an effective material that can resist nonspecific protein adsorption and cell adhesion. About eight water molecules are tightly bound with one sulfobetaine (SB) unit, and additional water molecules over 8:1 ratio mainly swell the polySBMA matrix, which is obtained through the measurement of T(2) relaxation time by low-field nuclear magnetic resonance (LF-NMR). This result was also supported by the endothermic behavior of water/polySBMA mixtures measured by differential scanning calorimetry (DSC). Furthermore, by comparing both results of polySBMA and poly(ethylene glycol) (PEG), it is found that (1) the hydrated water molecules on the SB unit are more tightly bound than on the ethylene glycol (EG) unit before saturation, and (2) the additional water molecules after forming the hydration layer in polySBMA solutions show higher freedom than those in PEG. These results might illustrate the reason for higher resistance of zwitterionic materials to nonspecific protein adsorptions compared to that of PEGs.

Binding characteristics between polyethylene glycol (PEG) and proteins in aqueous solution

Abstract: Polymer–protein interactions are crucial for determining the activity of both polymer and protein for many bio-related applications. Poly(ethylene glycol) (PEG) as a well-known antifouling material is often coated on surfaces to form highly solvated brushes, which exhibit excellent protein-repellent properties. However, unlike surface-induced antifouling effects, little is known about the intrinsic PEG–protein interactions in aqueous solution, which is an important yet neglected problem. Here, we investigate the interactions between PEG and proteins in aqueous solution using fluorescence spectroscopy, atomic force microscopy (AFM), and nuclear magnetic resonance (NMR). Two important characteristics, molecular weight of PEG and mass ratio of PEG:protein, are examined to determine the effect of each on PEG–protein interactions as well as binding characteristics between PEG and proteins. In contrast to too long and too short PEG chains, collective results have shown that PEG with optimal molecular weight (MW) is more capable of interacting with proteins, which induces the conformational change of proteins through more stable binding sites and stronger interactions with long chain PEG. Enhanced PEG–protein interactions are likely due to the change of hydrophilicity to amphiphilicity of PEG with increasing MWPEG. In contrast to almost none or weak interactions of PEG surfaces with proteins, this work provides new evidence to demonstrate the existence of interactions between PEG and proteins in aqueous solution, which is important not only for better understanding of the structure–activity relationship of PEG both in solution and on surfaces, but also for the rational design of new PEG-based materials for specific applications.

Cartilage-inspired, lipid-based boundary-lubricated hydrogels

Abstract: The lubrication of hydrogels arises from fluid or solvated surface phases. By contrast, the lubricity of articular cartilage, a complex biohydrogel, has been at least partially attributed to nonfluid, lipid-exposing boundary layers. We emulated this behavior in synthetic hydrogels by incorporating trace lipid concentrations to create a molecularly thin, lipid-based boundary layer that renews continuously. We observed a 80% to 99.3% reduction in friction and wear relative to the lipid-free gel, over a wide range of conditions. This effect persists when the gels are dried and then rehydrated. Our approach may provide a method for sustained, extreme lubrication of hydrogels in applications from tissue engineering to clinical diagnostics.

Recent Progress in Cartilage Lubrication.

Abstract: Healthy articular cartilage, covering the ends of bones in major joints such as hips and knees, presents the most efficiently-lubricated surface known in nature, with friction coefficients as low as 0.001 up to physiologically high pressures. Such low friction is indeed essential for its well-being. It minimizes wear-and-tear and hence the cartilage degradation associated with osteoarthritis, the most common joint disease, and, by reducing shear stress on the mechanotransductive, cartilage-embedded chondrocytes (the only cell type in the cartilage), it regulates their function to maintain homeostasis. Understanding the origins of such low friction of the articular cartilage, therefore, is of major importance in order to alleviate disease symptoms, and slow or even reverse its breakdown. This progress report considers the relation between frictional behavior and the cellular mechanical environment in the cartilage, then reviews the mechanism of lubrication in the joints, in particular focusing on boundary lubrication. Following recent advances based on hydration lubrication, a proposed synergy between different molecular components of the synovial joints, acting together in enabling the low friction, has been proposed. Additionally, recent development of natural and bio-inspired lubricants is reviewed.

Nano based drug delivery systems: recent developments and future prospects

Abstract: Nanomedicine and nano delivery systems are a relatively new but rapidly developing science where materials in the nanoscale range are employed to serve as means of diagnostic tools or to deliver therapeutic agents to specific targeted sites in a controlled manner Nanotechnology offers multiple benefits in treating chronic human diseases by site-specific, and target-oriented delivery of precise medicines Recently, there are a number of outstanding applications of the nanomedicine (chemotherapeutic agents, biological agents, immunotherapeutic agents etc) in the treatment of various diseases The current review, presents an updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs (eg, natural products) and selective diagnosis through disease marker molecules The opportunities and challenges of nanomedicines in drug delivery from synthetic/natural sources to their clinical applications are also discussed In addition, we have included information regarding the trends and perspectives in nanomedicine area

Antifouling membranes for sustainable water purification: strategies and mechanisms

Abstract: One of the greatest challenges to the sustainability of modern society is an inadequate supply of clean water. Due to its energy-saving and cost-effective features, membrane technology has become an indispensable platform technology for water purification, including seawater and brackish water desalination as well as municipal or industrial wastewater treatment. However, membrane fouling, which arises from the nonspecific interaction between membrane surface and foulants, significantly impedes the efficient application of membrane technology. Preparing antifouling membranes is a fundamental strategy to deal with pervasive fouling problems from a variety of foulants. In recent years, major advancements have been made in membrane preparation techniques and in elucidating the antifouling mechanisms of membrane processes, including ultrafiltration, nanofiltration, reverse osmosis and forward osmosis. This review will first introduce the major foulants and the principal mechanisms of membrane fouling, and then highlight the development, current status and future prospects of antifouling membranes, including antifouling strategies, preparation techniques and practical applications. In particular, the strategies and mechanisms for antifouling membranes, including passive fouling resistance and fouling release, active off-surface and on-surface strategies, will be proposed and discussed extensively.

Zwitteration: Coating Surfaces with Zwitterionic Functionality to Reduce Nonspecific Adsorption

Abstract: Coating surfaces with thin or thick films of zwitterionic material is an effective way to reduce or eliminate nonspecific adsorption to the solid/liquid interface. This review tracks the various approaches to zwitteration, such as monolayer assemblies and polymeric brush coatings, on micro- to macroscopic surfaces. A critical summary of the mechanisms responsible for antifouling shows how zwitterions are ideally suited to this task.

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

Abstract: The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ev...