Nano LIFE

Pegylation, as a simple procedure to attach hydrophilic polyethylene glycol (PEG) onto therapeutic molecule or drug carriers has been utilized widely to deliver small molecules, proteins and peptides. It was first reported in 1970s by Dr. Frank Davis of Rutgers University and Dr. Abuchowsky in the studies of PEG modified albumin and catalase. The significance of this method at that time was able to successfully modify the enzyme with better hydrophilicity but also keep the enzymatic activity. The employment of PEG has provided superior stability of drug delivery systems (DDS) and enhanced the circulation time in vivo. Simple conjugation of PEG chains with various molecular weights enables the possibility to regulate the properties of desired DDS and led to important contribution in targeting therapy and diagnosis. Pegylation has been reported to be able to protect peptides by shielding antigenic epitopes from reticuloendothelial (RES) clearance and avoid enzymes being recognized by immune system and avoid early degradation. In addition, utilization of PEG in DDS are reported with enhanced delivery efficiency, prolonged circulation time and improved stability, especially active enzymes and peptides drug delivery. In this paper, we will conclude current studies about Pegylated DDS and their biomedical applications from both in vitro and in vivo studies.

Surface-enhanced Raman scattering (SERS) has been widely studied and applied for over three decades. However, reliable SERS detection of molecules with low polarizability is still suffering from poor sensitivity and reproducibility. In this paper, we have reported a new strategy for performing quantitative SERS detection of Raman insensitive Glutathione (GSH), based on GSH-induced replacement of a highly Raman sensitive four-mercaptopyridine (MP) adsorbed on the surface of four-aminothiophenol (ATP) embedded Au-core/Ag-shell particles. This replacement led to a strong decrease of the MP SERS signal, which was used to determine the concentration of GSH. The adoption of GSH-induced Raman probe replacement leads to high sensitivity, while the use of internal reference method provides an improved accuracy of the GSH quantification.

Doxorubicin (DOX) has been extensively used in the clinic to treat malignant tumors such as leukemias and Hodgkin’s lymphoma. However, the severe cardiotoxicity associated with the use of DOX requests the development of alternative and efficient pharmaceutical formulations. The PEGylated liposome of DOX can significantly reduce the cardiotoxicity but still lacks the active targeting towards cancer cells. Modification of liposomal DOX with active ligands would then be a rational approach to enhance the transportation of the toxin into tumor cells. Currently used targeting ligands include antibodies, proteins, small molecules, and peptides. By virtue of the advantages such as easy preparation, lower cost, and elevated resistance to enzymatic degradation, peptides are attracting a significant amount of interest as active targeting ligands for pharmaceutics. In this paper, we will briefly discuss the application of peptide ligands for the improvement of the therapeutic efficacy of liposomal DOX.

With the promising applications in artificial intelligence systems and wearable health care devices, great efforts have been devoted to develop advanced pressure sensors. Graphene-based materials are promising pressure sensor materials due to the excellent electrical conductivity, outstanding mechanical properties and large surface area. This review summarizes the recent advances and progress in graphene and graphene-based pressure sensors. Perspectives and challenges in this exciting field are also highlighted and discussed.

The extraordinary physiochemical properties of carbon nanotubes (CNTs) stimulated their wide application in biosensing research. Nanotube characteristics of fast electron transport, large surface area, high strength, excellent catalytic activity and good chemical stability contribute to ultrasensitive, highly selective and stable CNT biosensors. Among the various CNT biosensors, the field-effect transistor (FET) architecture has received tremendous attention due to the advantages of high performance, miniaturization, and capability for mass production. In this paper, we address recent advances in the development of CNT biosensors based on FETs. The synthesis and properties of CNTs are discussed, along with their integration into biosensors. Recent progress in device fabrication, including CNT functionalization, attachment, and bioreceptor immobilization in CNT-based FET biosensors are highlighted. Examples in medical, food and environmental fields are illustrated.

The one-dimensional (1D) self-assembly of $\pi$-electron molecules offers efficient strategies to enhance energy and charge transfer via highly ordered and conductive $\pi -\pi$ stacking of the chromophores. The chromophore rich nanostructures have great potential to serve as promising candidate materials for optoelectronic devices. However, the design and control of highly ordered nanostructures with multicolored chromophore redox gradients require finely chosen synthetic strategies and a delicate balance of supramolecular interactions. In this paper, we will introduce new strategies focused on self-assembly of nanofibers based on lysine derivatives functionalized with multi colored chromophores.

With the rise of graphene, there is growing attention on two-dimensional (2D) materials in the physical science community during the last decade. Most studies to date focus on the rich set of their superior electrical, optical, catalytic and electrochemical properties and highlight the encouraging opportunities for developing next generation electronics, optoelectronics, catalysis, and energy storage technologies. On the contrary, the biomedicine community has barely recognized the potential of these materials other than graphene. There are very limited published studies on these materials’ biological effects and biomedical applications. Here, we present a brief overview of 2D materials and discuss their potential for biomedical applications in hope of raising biomedical researchers’ awareness of the great opportunities associated with these materials. We first discuss the emergence of 2D materials and review two most important prerequisites for 2D materials’ biomedical applications, synthesis and biocompatibility. We then categorize the existing studies on 2D materials’ biomedical applications into biosensing, drug/gene delivery, antimicrobial, bioimaging and multimode therapeutic applications. We would put special emphasis on the great flexibility of various rational combinations of 2D material superior properties for the design and construction of assorted forms of reagents or devices with highly effective simultaneous diagnostic and therapeutic functions (or theranostics functions). At last, the newly emerging 2D black phosphorous with very rare and interesting properties is introduced as the next promising and important 2D materials to study in the upcoming years.

Drug delivery as a strategy to improve the effect of therapeutic treatment is gaining tremendous interest in biomedical research. The recent advancement in microfluidic technique designed to precisely control the liquid at micro or nano liter level has shed some new lights on reshaping the ongoing drug delivery research. In this aspect, this present mini-review gives an overview on the potential applications of microfluidic technique in the area of drug delivery, which basically covers the fabrication of drug delivery carriers and the design of microfluidic-based smart systems for localized in vivo drug delivery.

We report a thorough investigation of triplet–triplet annihilation upconversion (TTA-UC) in the silicone core/silica shell hollow nanoparticles (SSNPs). The results demonstrate that Platinum(II) octaethylporphyrin (PtOEP) and 9, 10-diphenylanthracene (DPA) were successfully captured in the hollow particles. It was also observed that TTA upconversion intensity from SSNPs increases with the concentration of DPA increasing. The mobility of chromophores was improved by the liquid core of the SSNPs, leading to the increasing of TTA-UC intensity. These results shed light onto the strategies to construct TTA-UC systems in solid substrates.

Tissue engineering is intended to manipulate living cells to help develop substitutes for native tissues or remodel tissue. Bioartificial tissues are commonly explored in various tissue engineering ventures to overcome the disadvantages of working with native tissue. Poly(propylene fumarate) is a potential biomaterial for bioartificial bone grafts. The polymer’s many desirable physical and chemical properties have drawn significant research interest. This miniature review is intended to cover a small portion of the investigations of poly(propylene fumarate) as a bone tissue engineering biomaterial.