Hydrogen-bonding topological remodeling modulated ultra-fine bacterial cellulose nanofibril-reinforced hydrogels for sustainable bioelectronics.

Bacterial cellulose (BC) with its inherent nanofibrils framework is an attractive building block for the fabrication of sustainable bioelectronics, but there still lacks an effective and green strategy to regulate the hydrogen-bonding topological structure of BC to improve its optical transparency and mechanical stretchability. Herein, we report an ultra-fine nanofibril-reinforced composite hydrogel by utilizing gelatin and glycerol as hydrogen-bonding donor/acceptor to mediate the rearrangement of the hydrogen-bonding topological structure of BC. Attributing to the hydrogen-bonding structural transition, the ultra-fine nanofibrils were extracted from the original BC nanofibrils, which reduced the light scattering and endowed the hydrogel with high transparency. Meanwhile, the extracted nanofibrils were connected with gelatin and glycerol to establish an effective energy dissipation network, leading to an increase in stretchability and toughness of hydrogels. The hydrogel also displayed tissue-adhesiveness and long-lasting water-retaining capacity, which acted as bio-electronic skin to stably acquire the electrophysiological signals and external stimuli even after the hydrogel was exposing to air condition for 30 days. Moreover, the transparent hydrogel could also serve as a smart skin dressing for optical identification of bacterial infection and on-demand antibacterial therapy after combined with phenol red and indocyanine green. This work offers a strategy to regulate the hierarchical structure of natural materials for designing skin-like bioelectronics toward green, low cost, and sustainability.

Hydrogel-Integrated Multimodal Response as a Wearable and Implantable Bidirectional Interface for Biosensor and Therapeutic Electrostimulation.

A hydrogel that fuses long-term biologic integration, multimodal responsiveness, and therapeutic functions has received increasing interest as a wearable and implantable sensor but still faces great challenges as an all-in-one sensor by itself. Multiple bonding with stimuli response in a biocompatible hydrogel lights up the field of soft hydrogel interfaces suitable for both wearable and implantable applications. Given that, we proposed a strategy of combining chemical cross-linking and stimuli-responsive physical interactions to construct a biocompatible multifunctional hydrogel. In this hydrogel system, ureidopyrimidinone/tyramine (Upy/Tyr) difunctionalization of gelatin provides abundant dynamic physical interactions and stable covalent cross-linking; meanwhile, Tyr-doped poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) acts as a conductive filler to establish electrical percolation networks through enzymatic chemical cross-linking. Thus, the hydrogel is characterized with improved conductivity, conformal biointegration features (i.e., high stretchability, rapid self-healing, and excellent tissue adhesion), and multistimuli-responsive conductivity (i.e., temperature and urea). On the basis of these excellent performances, the prepared multifunctional hydrogel enables multimodal wearable sensing integration that can simultaneously track both physicochemical and electrophysiological attributes (i.e., motion, temperature, and urea), providing a more comprehensive monitoring of human health than current wearable monitors. In addition, the electroactive hydrogel here can serve as a bidirectional neural interface for both neural recording and therapeutic electrostimulation, bringing more opportunities for nonsurgical diagnosis and treatment of diseases.

An upconversion nanoparticle-integrated fibrillar scaffold combined with a NIR-optogenetic strategy to regulate neural cell performance.

Optogenetics using light-sensitive proteins such as calcium transport channel rhodopsin (CatCh) opens up new possibilities for non-invasive remote manipulation of neural function. However, current optogenetic approaches for neurological disorder therapies rely on visible light excitation and are rarely applied to neurogenesis and nerve regeneration. Herein, we propose a new strategy for tissue engineering which combines optogenetic technology and biomimetic nerve scaffolds. Upconversion nanoparticles (UCNPs) were synthesized and integrated with oriented fibrillar PCL membranes with a collagen coating to establish neuro-matrix interfaces. Benefiting from the excellent bioactivity, oriented fibrillation and NIR-photoresponsivity, the CatCh-transfected PC12 cells on these interfaces exhibited enhanced cell elongation and neurite extension, as well as upregulated neurogenesis upon NIR excitation. Furthermore, a UCNP-integrated scaffold as an optogenetic actuator allowed NIR to penetrate dermal tissues to mediate neural activation, with an efficiency comparable to that of a 470 nm blue light. Compared with current visible light-excited optogenetics, our composite scaffold-mediated NIR stimulation addresses the problem of tissue penetration and will enable less-invasive neurofunctional manipulation, with the potential for remote therapy.

Complete mitochondrial genome of the hardnose shark Carcharhinus macloti (Carcharhiniformes: Carcharhinidae).

The complete mitochondrial genome of Carcharhinus macloti was determined in this study. It is 16,701 bp in length and contains 37 genes with the typical gene order and transcriptional orientation in vertebrates. A total of 29 bp overlaps and 29 bp short intergenic spaces located in 22 gene junctions. The overall base composition is 31.6% A, 26.2% C, 13.0% G and 29.2% T. Two start codons (ATG and GTG) and three stop codons (AGG, TAG and TAA/T) were found in 13 protein-coding genes. The length of 22 tRNA genes ranged from 66 bp (tRNA-Ser2) to 75 bp (tRNA-Leu1). The tRNA-Ser2 (GCU) lacks the dihydrouridine arm by a simple loop and can not be folded into the typical cloverleaf structure. The control region is 1066 bp in length with high A+T content (68.2%).

Complete mitochondrial genome of the humpback grouper Cromileptes altivelis.

The complete mitochondrial genome (16,497 bp) of the humpback grouper Cromileptes altivelis is first presented in this study. The gene arrangement and translate orientation of C. altivelis is identical to most vertebrates, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a putative control region. The overall nucleotide composition of the H-strand is 29.80% A, 26.23% T, 15.67% G and 29.02% C. The origin of the light-strand replication was identified between the tRNA-Asn and tRNA-Cys genes, while the termination associated sequence (TAS) and conserved sequence blocks (CSB1-3) were identified in the control region.

[Genome sequencing and analysis of the bovine viral diarrhea virus-2 strain JZ05-1 isolated in China].

Bovine viral diarrhea virus (BVDV) is a member of the genus Pestivirus, which is a widespread problem for beef and dairy herds, and has given rise to a significant loss in the livestock industry all over the world. The BVDV strain JZ05-1 isolated from cattle in Jilin, China generated cytopathic effect (CPE) in MDBK cells. Eight overlapped gene fragments were amplified by RT-PCR and sequenced, the complete genom sequence of BVDV strain JZ05-1 was assembled. According to the results, the JZ05-1 genome was composed of 12285 nucleotides in length (GenBank accession No. GQ888686), which could be divided into three regions: a 387 nt 5'-untranslated region (UTR), a 11694 nt single large open reading frame encoding a polyprotein, and a 204 nt 3'-UTR. The 5'-UTR and genome sequences were analyzed by sequence alignment and construction of phylogenetic trees. The strain JZ05-1 was classified as BVDV type 2a. The BVDV-2 strain JZ05-1 genome showed high similarity to the p11Q isolated in Canada and the XJ-04 isolated in China, with 90% and 91% identity in nucleotide sequence, respectively. Compared with the similarity within the BVDV-2 genotype (96%), the JZ05-1 had low sequence similarity to other BVDV-2 strains.