Synergistic Poly(lactic acid) Antibacterial Surface Combining Superhydrophobicity for Antiadhesion and Chlorophyll for Photodynamic Therapy.

The problem of nosocomial infections caused by bacterial growth on material surfaces is an urgent threat to public health. Although numerous materials and methods have been explored to fight against infections, the methods are complicated and the materials are slightly toxic. It is highly desirable to develop an antibacterial strategy that kills bacteria effectively without drug resistance and cytotoxicity. Herein, we present a synergistic antibacterial polylactic acid (PLA) surface with superhydrophobic antibacterial adhesion and photodynamic bactericidal activity. Initially, the surface displayed low-adhesion superhydrophobicity and resisted most bacterial adhesion. Furthermore, completely non-toxic chlorophyll possessed excellent photodynamic bactericidal properties under non-toxic visible light, which was incorporated into micro-/nanoscale PLA surfaces. We achieved efficient antibacterial activity using completely non-toxic materials and a facile non-solvent-induced phase separation process. This non-toxic, simple, good biocompatible, and no drug-resistant strategy has great advantages in combating bacterial infections.

Palliative pain relief and safety of percutaneous radiofrequency ablation combined with cement injection for bone metastasis.

PURPOSE: To investigate the pain relief effect and safety of percutaneous radiofrequency ablation (RFA) with a multitined electrode combined with cement injection in patients with painful metastatic bone tumors. MATERIALS AND METHODS: Sixteen patients with 34 osteolytic metastatic lesions were treated with RFA including 4 males and 12 females (age range 54-84). Thirteen patients with spinal metastases received additional cement injection. Medical imaging, a visual analog scale (VAS) and the EORTC QLQ-C30 were performed to evaluate the metastatic lesion, pain and quality of life, respectively, before and after RFA and at follow-ups. RESULTS: The RFA and/or vertebroplasty with cement injection were successful in all patients (100%). Except for one patient who had cement leakage, no intraprocedural complications occurred. After RFA, severe refractory pain was greatly relieved in all patients, with pretreatment VAS score of 8.1 ± 1.4 significantly reduced to 5.5 ± 1.1 at 24 h, 2.8 ± 0.6 at 1 week and 1.4 ± 0.8 at 6 months (P < 0.01). The EORTC QLQ-C30 scale at 1 month demonstrated significant improvement (P < 0.05) in the physical (P = 0.03) and emotion function (P = 0.003), global health status (P = 0.002), pain (P = 0.001) and insomnia (P = 0.002). The analgesics were reduced after the procedure and stopped 2 months later in all patients, with greatly improved quality of life and no apparent pain. Followed up for 6-12 months, all patients remained alive with no recurrence of pain. Palliative pain relief and safety of percutaneous radiofrequency ablation combined with cement injection for bone metastasis. CONCLUSION: RFA with or without bone cement is safe and effective in the palliative treatment of pain caused by metastatic bone tumors.

Nonsolvent-assisted fabrication of multi-scaled polylactide as superhydrophobic surfaces.

The solution-processing fabrication of superhydrophobic surfaces is currently intriguing, owing to high-efficiency, low cost, and energy-consuming. Here, a facile nonsolvent-assisted process was proposed for the fabrication of the multi-scaled surface roughness in polylactide (PLA) films, thereby resulting in a significant transformation in the surface wettability from intrinsic hydrophilicity to superhydrophobicity. Moreover, it was found that the surface topographical structure of PLA films can be manipulated by varying the compositions of the PLA solutions. And the samples showed superhydrophobic surfaces as well as high melting enthalpy and crystallinity. In particular, a high contact angle of 155.8° together with a high adhesive force of 184 µN was yielded with the assistance of a multi-nonsolvent system, which contributed to the co-existence of micro-/nano-scale hierarchical structures.

Injectable Conductive Hydrogel with Self-Healing, Motion Monitoring, and Bacteria Theranostics for Bioelectronic Wound Dressing.

Wounds at joints are difficult to treat and tend to recover more slowly due to the frequent motions. When using traditional hydrogel dressings, they are easy to crack and undergo bacterial infection, difficult to match and monitor the irregular wounds. Integrating multiple functions within a hydrogel dressing to achieve intelligent wound monitoring and healing remains a significant challenge. In this research, a multifunctional hydrogel is developed based on polysaccharide biopolymer, poly(vinyl alcohol), and hydroxylated graphene through dynamic borate ester bonding and supramolecular interaction. The prepared hydrogel not only exhibits rapid self-healing (within 60 s), injectable, conductive and motion monitoring properties, but also realizes in situ bacterial sensing and killing functions. It shows excellent bacterial sensitivity (within 15 min) and killing ability via the changes of electrical signals and photothermal therapy, avoiding the emergence of drug-resistant bacteria. In vivo experiments prove that the hydrogel can promote wound healing effectively. In addition, it displays great electromechanical performance to achieve real-time monitoring and prevent re-tearing of the wound at human joints. The injectable pH-responsive hydrogel with good biocompatibility demonstrates considerable potential as multifunctional bioelectronic dressing for the detection, treatment, management, and healing of infected joint wounds.

Stimuli-Responsive Antibacterial Materials: Molecular Structures, Design Principles, and Biomedical Applications.

Infections are regarded as the most severe complication associated with human health, which are urgent to be solved. Stimuli-responsive materials are appealing therapeutic platforms for antibacterial treatments, which provide great potential for accurate theranostics. In this review, the advantages, the response mechanisms, and the key design principles of stimuli-responsive antibacterial materials are highlighted. The biomedical applications, the current challenges, and future directions of stimuli-responsive antibacterial materials are also discussed. First, the categories of stimuli-responsive antibacterial materials are comprehensively itemized based on different sources of stimuli, including external physical environmental stimuli (e.g., temperature, light, electricity, salt, etc.) and bacterial metabolites stimuli (e.g., acid, enzyme, redox, etc.). Second, structural characteristics, design principles, and biomedical applications of the responsive materials are discussed, and the underlying interrelationships are revealed. The molecular structures and design principles are closely related to the sources of stimuli. Finally, the challenging issues of stimuli-responsive materials are proposed. This review will provide scientific guidance to promote the clinical applications of stimuli-responsive antibacterial materials.

Intrinsic carbon nanotube liquid crystalline elastomer photoactuators for high-definition biomechanics.

Photoresponsive soft actuators with the unique merits of flexibility, contactless operation, and remote control have huge potential in technological applications of bionic robotics and biomedical devices. Herein, a facile strategy was proposed to prepare an intrinsically-photoresponsive elastomer by chemically grafting carbon nanotubes (CNTs) into a thermally-sensitive liquid-crystalline elastomer (LCE) network. Highly effective dispersion and nematic orientation of CNTs in the intrinsic LCE matrix were observed to yield anchoring energies ranging from 1.65 × 10-5 J m-2 to 5.49 × 10-7 J m-2, which significantly enhanced the mechanical and photothermal properties of the photoresponsive elastomer. When embedding an ultralow loading of CNTs (0.1 wt%), the tensile strength of the LCE increased by 420% to 13.89 MPa (||) and 530% to 3.94 MPa (⊥) and exhibited a stable response to repeated alternating cooling and heating cycles, as well as repeated UV and infrared irradiation. Furthermore, the shape transformation, locomotion, and photo-actuation capabilities allow the CNT/LCE actuator to be applied in high-definition biomechanical applications, such as phototactic flowers, serpentine robots and artificial muscles. This design strategy may provide a promising method to manufacture high-precision, remote-control smart devices.

Functional biomaterials towards flexible electronics and sensors.

Biomaterials have gained increasing attention in the fabrication of a variety of flexible electronics due to their tunable solubility, robust mechanical property, multi-active binding sites, and excellent biocompatible and biodegradable characterization as well. Here, we review the recent progress of bio-based materials in flexible sensors, mainly describe nature biomaterials (silk fibroin, cellulose and chitin) and chemical-synthesized biomaterials as well as their applications in health monitors, biosensor, human-machine interactions (HMIs) and more, and highlight the current opportunities and challenges that lay ahead in mounting numbers of academia and industry. Furthermore, we expect this review could contribute to unveiling the potentials of developing outstanding and eco-friendly sensors with biomaterials by utilization of printing techniques.