NIR-II Light Accelerated Prodrug Reduction of Pt(IV)-Incorporating Pseudo Semiconducting Polymers for Robust Degradation and Maximized Photothermal/Chemo-Immunotherapy.

Selective activation of Pt(IV) prodrugs within tumors is particularly attractive because of their low damage to normal tissues. However, current common activation via chemical/photoreduction of Pt(IV) prodrugs into Pt(II) counterparts is limited by undesirable spatial-temporal control over this reduction process and the ineffective tissue penetration depth of undesirable light. Here, a pseudo-conjugated-polymer is designed via Stille polymerization, resulting in PSP-Pt with a Pt(IV) prodrug of oxaliplatin (Oxa(IV)) in the polymer main chain that can be activated by NIR-II light. PSP-Pt can co-assemble with a commercially available lipid polymer, namely mPEG2k -DSPE, into NPPSP-Pt . Under 1064 nm light irradiation, NPPSP-Pt can be photoactivated to accelerate the Pt(IV) reduction to release oxaliplatin, thereby killing the cancer cells by photothermal effect and chemo-immunotherapy inside a mouse model with CT26 colon cancer. This work reports the application of NIR-II light for accelerating Pt(IV) reduction for cancer tumor therapy.

Degradable Pseudo Conjugated Polymer Nanoparticles with NIR-II Photothermal Effect and Cationic Quaternary Phosphonium Structural Bacteriostasis for Anti-Infection Therapy.

Photothermal therapy based on conjugated polymers represents a promising antibacterial strategy but still possesses notable limitations. Herein, degradable pseudo conjugated polymers (PCPs) containing photothermal molecular backbones and reactive oxygen species (ROS)-sensitive thioketal bonds are designed. Triphenylphosphine (PPh3 ) is introduced into PCPs to generate phosphonium-based PCPs (pPCPs), which further assembled with hyaluronic acid into pPCP nanoparticles (pPCP-NPs). pPCP-NPs with quaternary phosphonium cations selectively anchor on and destroy bacterial cell membranes through electrostatic action. Under 1064 nm laser irradiation, pPCP-NPs (pPCP-NPs/+L) produce near-infrared-II (NIR-II) photothermal antibacterial effect, thereby killing bacteria in a sustained manner. pPCP-NPs are readily degraded upon ROS abundant at infection sites, therefore exhibiting enough biosafety. pPCP-NPs/+L display an almost 100% bacterial inhibition rate in vitro and resultin a nearly complete recovery of bacteria-induced mouse wounds. A further metabolomics analysis denotes that pPCP-NPs/+L work in a concerted way to induce bacterial DNA damage, inhibit bacterial carbon/nitrogen utilization and amino acid/nucleotide synthesis. Taken together, degradable pPCP-NPs with both NIR-II photothermal effect and cationic phosphonium structural bacteriostasis provide a new avenue for antibiotics-alternative anti-infection therapy.

Bactericidal and antifouling electrospun PVA nanofibers modified with a quaternary ammonium salt and zwitterionic sulfopropylbetaine.

Bacterial adhesion and colonization on material surfaces have attracted great attention due to their potential threat to human health. Combining bactericidal and antifouling functions has been confirmed as an optimal strategy to prevent microbial infection. In this work, biodegradable electrospun polyvinyl alcohol (PVA) nanofibers were chosen due to its high specific area and abundant reactive hydroxyl groups. A quaternary ammonium salt (IQAS) and zwitterionic sulfopropylbetaine (ISB), both containing isocyanate (NCO) groups, were chemically bonded to the PVA nanofiber surface via a coupling reaction between the OH groups of the PVA nanofibers and the NCO groups of IQAS or ISB. The results indicated that the antimicrobial rates of PVA nanofibers modified by IQAS (0.5%) reached 99.9% against both gram-positive Staphylococcus aureus (S. aureus, ATCC 6538) and gram-negative Escherichia coli (E. coli, ATCC 25922). Additionally, the live/dead staining and cytotoxicity test indicated that the dual functional IQAS/ISB/PVA nanofibers exhibited excellent bactericidal and antifouling activities with low cytotoxicity. This work may provide practical guidelines to fabricate bactericidal and antifouling materials for healthcare applications, including but not limited to wound dressings, textile, food packaging and air filtration.

[Effect of functional appliance on upper airway in adolescent patients with skeletal Class II malocclusion].

PURPOSE: To investigate the effect of functional appliance on upper airway in adolescent patients with skeletal Class II malocclusion based on cone-beam CT (CBCT). METHODS: Thirty adolescent patients (male:female=1:1) with skeletal Class II malocclusion and their 30 counterparts with skeletal Class I malocclusion were selected. Skeletal Class II malocclusion patients were treated with Activator for 12 months on average, meanwhile skeletal Class I malocclusion patients were treated with fixed appliance without extraction. Cone-beam CT (CBCT) films were taken before and 12 months after treatment. Films of skeletal Class II malocclusion patients were measured (items about skeletal and upper airway, and the outline of upper airway depicted with 3D reconstruction) and compared with the reference standards and the measurements of their counterpart patients with skeletal Class I malocclusion. Independent t test was performed in inter-group comparison and paired t test was performed in inner-group comparison using SAS 8.0 software package. RESULTS: Before treatment, patients with skeletal Class II malocclusion showed decreased SNB and APDI value, increased ANB, Wits, and OJ compared with standard value and value of skeletal Class I malocclusion patients. In addition, decreased MPW and PAS value, and downsized volume of upper airway and transverse diameter minimum were found in skeletal Class II malocclusion patients. After treatment with Activator, patients with skeletal Class II malocclusion showed increased MPW and PAS value, and enlarged volume of upper airway and transverse diameter minimum. All values of skeletal items of patients with skeletal Class II malocclusion showed trends to get close to the reference standards and the values of skeletal Class I malocclusion patients. There was no significant difference between different genders of the two groups. CONCLUSIONS: Patients with skeletal Class II malocclusion have constructed upper airways. Treatment with Activator can increase the MPW and PAS values and enlarge volume of upper airway and transverse diameter minimum. Functional appliance can ameliorate the narrowness of upper airway for skeletal Class II patients.