The high susceptibility of the natural D-conformation of DNA (D-DNA) to nucleases greatly limits the application of DNA-templated silver nanoclusters (Ag NCs) in biological matrixes. Here we demonstrate that the L-conformation of DNA (L-DNA), the enantiomer of D-DNA, can also be used for the preparation of aptamer-Ag NCs. The extraordinary resistance of L-DNA to nuclease digestion confers much higher biostability to these NCs than those templated by D-DNA, thus making cell-type-specific imaging possible at physiological temperatures, using at least 100-times lower Ag NC concentration than reported D-DNA-templated ones. The L-DNA-templated metal NC probes with enhanced biostability might promote the applications of metal nanocluster probes in complex biological systems.

Carbon nanomaterials have been used to treat neurodegenerative diseases and neural disorders due to their diverse molecular structures. Corannulene is a three-dimensional π-bowl carbon nanomaterial that is different from planar PAHs, fullerenes and carbon nanotubes, but little is known about its biological functions. Herein, corannulene was functionalized with mPEG-DESP to prepare PEGylation corannulene nanoparticles (PEGylation CoNps). The synthesized PEGylation CoNps shows enhanced solubility and reduced aggregation when compared corannulene. Then, in vivo experiments were performed to determine the effects of PEGylation CoNps on the neural system. We found that PEGylation CoNps treatment increased short resting bouts, decreased locomotion activities and enhanced the response to stress. Most of these behavioral changes suggest that PEGylation CoNps lead to a greater reflection to stress, which is associated with neurotransmitter expression and neurogenesis. In line with the hypothesis, we found that PEGylation CoNps administration enhanced TH, DCX and MAP-2 expression in the hippocampus. These results indicated that PEGylation CoNps enhanced the neurogenesis of mice. Furthermore, pathological analysis showed that PEGylation CoNps caused little inflammation. These findings suggest that PEGylation CoNps are a potential functionalized carbon nanomaterial for promoting neurogenesis.

Polydimethylsiloxane (PDMS) is widely used as a cell culture platform to produce micro- and nano-technology based microdevices. However, the native PDMS surface is not suitable for cell adhesion and is always subject to bacterial pollution and cancer cell invasion. Coating the PDMS surface with antibacterial or anticancer materials often causes considerable harm to the non-cancer mammalian cells on it. We have developed a method to fabricate a biocompatible PDMS surface which not only promotes non-cancer mammalian cell growth but also has antibacterial and anticancer activities, by coating the PDMS surface with a Chinese herb extract, paeonol. Coating changes the wettability and the elemental composition of the PDMS surface. Molecular dynamic simulation indicates that the absorption of paeonol onto the PDMS surface is an energy favourable process. The paeonol-coated PDMS surface exhibits good antibacterial activity against both Gram-positive and Gram-negative bacteria. Moreover considerable antibacterial activity is maintained after the coated surface is rinsed or incubated in water. The coated PDMS surface inhibits bacterial growth on the contact surface and promotes non-cancer mammalian cell growth with low cell toxicity; meanwhile the growth of cancer cells is significantly inhibited. Our study will potentially guide PDMS surface modification approaches to produce biomedical devices.

A major issue in bone tissue engineering is the selection of biocompatible materials for implants, to reduce unwanted inflammatory reactions and promote cell adhesion. Bone tissue growth on suitable biomedical implants can shorten recovery and hospitalization after surgery. Therefore, a method to improve tissue-implant integration and healing would be of scientific and clinical interest. In this work, we permeated polydimethylsiloxane (PDMS) into carbon/carbon (C/C) composites (PDMS-C/C) and then coated it with 4,5-dihydroxyanthraquinone-2-carboxylic acid (rhein) to create rhein-PDMS-C/C to increase its biocompatibility and reduce the occurrence of inflammatory reactions. We measured in vitro adhesion and proliferation of MC3T3-E1 cells and bacteria to evaluate the biocompatibility and antimicrobial properties of C/C, PDMS-C/C, and rhein-PDMS-C/C. In vivo, x-ray and micro-CT evaluation three, six and nine weeks after surgery revealed that rhein-PDMS-C/C was more effective than PDMS-C/C and C/C composite in terms of antibacterial activity, cell adhesion and tissue growth. Compared with C/C and PDMS-C/C, rhein-PDMS-C/C could be suitable for clinical applications for bone tissue engineering.

Carbon debris and the resulting inflammatory reaction are major disadvantages of carbon/carbon (C/C) composites in repairing bone damage or impairment. These issues cause infection after orthopaedic surgeries and implantation surgeries. Therefore, the enhancement of the biocompatibility of carbon materials as implantable medical materials is investigated in the study of surface modification of orthopaedic scaffold materials. In this work, polydimethylsiloxane (PDMS) was introduced onto C/C composites to produce PDMS-C/C composites. The use of PDMS-C/C not only prevented the carbon debris but also enhanced the mechanical flexibility. In addition, paeonol (Pae) was coated on the PDMS-C/C with the aim of improving the antibacterial properties and biocompatibility of PDMS-C/C. In vitro evaluations of the bacteria at 2 and 4 h indicated that Pae-PDMS-C/C exhibited an improved antibacterial effect, reaching 32.3% at 4 h, and greater cell adhesion and proliferation activity than C/C and PDMS-C/C. Importantly, the in vivo study demonstrated that the implantation of Pae-PDMS-C/C efficiently promoted new bone formation based on an evaluation of a 3D reconstruction and histological observations. The in vivo and in vitro studies illustrated that Pae-PDMS-C/C possesses better biological effects and biocompatibility and will help to expand the application of carbon materials in medical implantation.