Application of Metagenomic High-Throughput Sequencing in a Rare Case of Multisite Infection With Two Microorganisms After Total Knee Arthroplasty.

Postoperative deep infection is usually identified by microbial culture. However, frequent false-negative results have severely limited effective treatment. We report a rare case of intra-articular and paravertebral infection after total knee arthroplasty caused by Mycoplasma hominis and Ureaplasma urealyticum, with multiple negative microbial culture results. Eventually, the pathogens were identified using metagenomic high-throughput sequencing, and the patient was successfully treated with several "old" antibiotics. We analyze the clinical characteristics of this patient and systematically describe the application of high-throughput sequencing and antibiotics. [Orthopedics. 2024;47(1):e52-e56.].

Precise Patellar Tendon Insertion Protection and Osteotomy Surface Advantage of Transtibial Tuberosity-High Tibial Osteotomy.

OBJECTIVE: Medial opening wedge high tibial osteotomy (HTO) is successful in the treatment of knee osteoarthritis with medial compartment stenosis and tibial varus deformity, but patella infera is the main complication. This study aims to design a new medial tibial open osteotomy scheme, transtibial tuberosity-high tibial osteotomy (TT-HTO), which can fully protect the patellar tendon insertion. In addition, the area of the osteotomy surface and wedge volume were evaluated in TT-HTO, biplanar distal tibial tuberosity osteotomy (biplanar-DTO), and uniplanar-DTO to evaluate the potential advantages of this technology in bone healing. METHODS: The tibial tubercle was divided into four equal sections from proximal to distal, which were defined as zones A, B, C, and D. From September to December 2020, the imaging examinations of 200 patients (95 males and 105 females) with a mean age of 40.6 years (range 19-60 years) were evaluated to observe the zonation of the tibial tubercle where the insertion of the patellar tendon is located. Then, 59 patients (23 males and 36 females) with a mean age 59.6 years (range 43-77 years), for a total of 69 knees (32 right and 37 left), who underwent routine knee surgery were observed and verified. According to the position of the patellar tendon insertion, TT-HTO was designed. Fifteen tibial sawbones were divided equally into three groups: TT-HTO; biplanar-DTO; and uniplanar-DTO. The total area of the osteotomy surface was compared using the graph paper method. The wedge volume at wedge heights of 10 mm was compared among osteotomy types using the plasticine Archimedes principle. One-way repeated-measures analysis of variance was used to compare the total area of the osteotomy surface and the wedge volume. RESULTS: The osteotomy line of TT-HTO passes through the boundary point of zones B and C of the tibial tubercle to fully protect the insertion point of the patellar tendon. The total area of the osteotomy surface in TT-HTO and biplanar-DTO was significantly larger than that in uniplanar-DTO (P < 0.05). The wedge volume in uniplanar-DTO was significantly smaller than that in TT-HTO and biplanar-DTO (P < 0.05). No significant differences in the osteotomy surface and the wedge volume were identified between TT-HTO and biplanar-DTO. CONCLUSION: TT-HTO can protect the patellar tendon insertion and avoid postoperative patella infera. The osteotomy surface is large and located in an area of cancellous bone, which ensures its good healing characteristics.

Light triggered nanoscale biolistics for efficient intracellular delivery of functional macromolecules in mammalian cells.

Biolistic intracellular delivery of functional macromolecules makes use of dense microparticles which are ballistically fired onto cells with a pressurized gun. While it has been used to transfect plant cells, its application to mammalian cells has met with limited success mainly due to high toxicity. Here we present a more refined nanotechnological approach to biolistic delivery with light-triggered self-assembled nanobombs (NBs) that consist of a photothermal core particle surrounded by smaller nanoprojectiles. Upon irradiation with pulsed laser light, fast heating of the core particle results in vapor bubble formation, which propels the nanoprojectiles through the cell membrane of nearby cells. We show successful transfection of both adherent and non-adherent cells with mRNA and pDNA, outperforming electroporation as the most used physical transfection technology by a factor of 5.5-7.6 in transfection yield. With a throughput of 104-105 cells per second, biolistic delivery with NBs offers scalable and highly efficient transfections of mammalian cells.

Biomechanical analysis of the drilling parameters for early osteonecrosis of the femoral head.

BACKGROUND AND OBJECTIVE: Core decompression is a surgical procedure commonly used to treat the early osteonecrosis of the femoral head. However, It is not known whether different drilling parameters affect postoperative biomechanical strength. This study aimed to analyze the mechanical stability of different drilling locations and diameters of core decompression using finite element analysis. METHODS: Finite element models were established based on computed tomography images obtained from five healthy participants, including the different drilling locations (Lesser trochanter: Above, Parallel, and Below) and diameters. Biomechanical parameters including stiffness and stress were evaluated under slow running loads. RESULTS: At the same drilling diameter, the femoral stiffness was highest (p < 0.05) in the Above group and lowest in the Below group, while the maximum equivalent stress of the entry area and the necrotic area was highest (p < 0.05) in the Below group and lowest in the Above group. With the increase of drilling diameters, the stiffness decreased and its decreased percentage comparing the preoperative: Above (1.06-8.82%), Parallel (2.51-13.61%), and Below (3.99-15.06%). The maximum equivalent stress of the entry area and necrotic area increased as the drilling diameter increased, and its increased percentage comparing the preoperative, for the entry area: Above (14.11-219.58%), Parallel (35.91-306.37%), and Below (46.12-240.98%); for the necrotic area: Above (13.64-114.69%), Parallel (29.37-187.76%), and Below (44.76-202.10%). The range of safety drilling parameters (SDP) was obtained (Below<9 mm, Parallel<11 mm, and Above<13 mm) by comparing the maximum equivalent stress of two areas and its yield strength. For patients of different sizes and normal bone mineral density (BMD), the maximum equivalent stress of the two areas did not exceed its yield strength using the range of SDP, except for the patients with abnormal BMD (Osteoporosis) or high body mass index (BMI≥28 kg/m2). CONCLUSIONS: The biomechanical properties of early osteonecrosis of the femoral head deceased with increasing drilling diameters parameters, especially at the location below the lesser trochanter. The SDP (Below<9 mm, Parallel<11 mm, and Above<13 mm) is a suitable reference for most patients to perform slow running postoperatively, while it may be not suitable for patients with osteoporosis or obesity.

Core-shell microparticles: From rational engineering to diverse applications.

Core-shell microparticles, composed of solid, liquid, or gas bubbles surrounded by a protective shell, are gaining considerable attention as intelligent and versatile carriers that show great potential in biomedical fields. In this review, an overview is given of recent developments in design and applications of biodegradable core-shell systems. Several emerging methodologies including self-assembly, gas-shearing, and coaxial electrospray are discussed and microfluidics technology is emphasized in detail. Furthermore, the characteristics of core-shell microparticles in artificial cells, drug release and cell culture applications are discussed and the superiority of these advanced multi-core microparticles for the generation of artificial cells is highlighted. Finally, the respective developing orientations and limitations inherent to these systems are addressed. It is hoped that this review can inspire researchers to propel the development of this field with new ideas.

Photothermal nanofibres enable safe engineering of therapeutic cells.

Nanoparticle-sensitized photoporation is an upcoming approach for the intracellular delivery of biologics, combining high efficiency and throughput with excellent cell viability. However, as it relies on close contact between nanoparticles and cells, its translation towards clinical applications is hampered by safety and regulatory concerns. Here we show that light-sensitive iron oxide nanoparticles embedded in biocompatible electrospun nanofibres induce membrane permeabilization by photothermal effects without direct cellular contact with the nanoparticles. The photothermal nanofibres have been successfully used to deliver effector molecules, including CRISPR-Cas9 ribonucleoprotein complexes and short interfering RNA, to adherent and suspension cells, including embryonic stem cells and hard-to-transfect T cells, without affecting cell proliferation or phenotype. In vivo experiments furthermore demonstrated successful tumour regression in mice treated with chimeric antibody receptor T cells in which the expression of programmed cell death protein 1 (PD1) is downregulated after nanofibre photoporation with short interfering RNA to PD1. In conclusion, cell membrane permeabilization with photothermal nanofibres is a promising concept towards the safe and more efficient production of engineered cells for therapeutic applications, including stem cell or adoptive T cell therapy.

Bubble Forming Films for Spatial Selective Cell Killing.

Photodynamic and photothermal cell killing at the surface of tissues finds applications in medicine. However, a lack of control over heat dissipation following a treatment with light might damage surrounding tissues. A new strategy to kill cells at the surface of tissues is reported. Polymeric films are designed in which iron oxide nanoparticles are embedded as photosensitizers. Irradiation of the films with pulsed laser light generates water vapor bubbles at the surface of the films. It is found that "bubble-films" can kill cells in close proximity to the films due to mechanical forces which arise when the bubbles collapse. Local irradiation of bubble-films allows for spatial selective single cell killing. As nanosurgery becomes attractive in ophthalmology to remove superficial tumors, bubble-films are applied on the cornea and it is found that irradiation of the bubble-films allows spatial and selective killing of corneal cells. As i) the photosensitizer is embedded in the films, which reduces its uptake by cells and spreading into tissues and ii) the bubble-films can be removed from the tissue after laser treatment, while iii) a low laser fluence is sufficient to generate vapor bubbles, it is foreseen that bubble-films might become promising for safe resection of superficial tumors.

Carbon quantum dots as a dual platform for the inhibition and light-based destruction of collagen fibers: implications for the treatment of eye floaters.

Common in myopia and aging, vitreous opacities arise from clumped collagen fibers within the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause significant impairment in vision-related quality-of-life, representing an unmet and underestimated medical need. One therapeutic approach could be the use of versatile light-responsive nanostructures which (i) interfere with the formation of collagen fibers and/or (ii) destroy aggregates of vitreous collagen upon pulsed-laser irradiation at low fluences. In this work, the potential of positively and negatively charged carbon quantum dots (CQDs) to interfere with the aggregation of type I collagen is investigated. We demonstrate that fibrillation of collagen I is prevented most strongly by positively charged CQDs (CQDs-2) and that pulsed-laser illumination allowed to destroy type I collagen aggregates and vitreous opacities (as obtained from patients after vitrectomy) treated with CQDs-2.

A novel xanthan gum-based conductive hydrogel with excellent mechanical, biocompatible, and self-healing performances.

Tough and conductive hydrogels are promising materials for various applications. However, it remains a great challenge to develop an integrated hydrogel combining outstanding mechanical, conductive, and self-healing performances. Herein, we prepared a conductive, self-healing, and tough hydrogel by constructing synergistic multiple interaction among montmorillonite (MMT), Poly (acrylamide-co-acrylonitrile) (P(AAm-co-AN)), xanthan gum (XG) and ferric ion (Fe3+). The obtained xanthan gum/montmorillonite/Poly (acrylamide-co-acrylonitrile) (XG/MMT/PAAm) hydrogels showed high strain stress (0.48 MPa) and compressive stress (5.9 MPa) as well as good shape recovery after multiple loading-unloading cycle tests. Moreover, the XG/MMT/PAAm hydrogels have distinctive features such as remarkable resistance to fatigue and harsh environments, insensitivity to notch, conductive, biocompatible, pH-dependent swelling behaviors and self-healing. Therefore, the as-fabricated hydrogel delivers a new prospect for its applications in various fields, such as flexible conductive device and tissue engineering.

Materials and Technologies to Combat Counterfeiting of Pharmaceuticals: Current and Future Problem Tackling.

The globalization of drug trade leads to the expansion of pharmaceutical counterfeiting. The immense threat of low quality drugs to millions of patients is considered to be an under-addressed global health challenge. Analytical authentication technologies are the most effective methods to identify active pharmaceutical ingredients and impurities. However, most of these analytical testing techniques are expensive and need skilled personnel. To combat counterfeiting of drugs, the package of an increasing number of drugs is being protected through advanced package labeling technologies. Though, package labeling is only effective if the drugs are not repackaged. Therefore "in-drug labeling," instead of "drug package labeling," may become powerful tools to protect drugs. This review aims to overview how advanced micro- and nanomaterials might become interesting markers for the labeling of tablets and capsules. Clearly, how well such identifiers can be integrated into "solid drugs" without compromising drug safety and efficacy remains a challenge. Also, incorporation of tags has so far only been reported for the protection of solid drug dosage forms. No doubts that in-drug labeling technologies for "liquid drugs," like injectables which contain expensive peptides, monoclonal antibodies, vaccines, dermal fillers, could help to protect them from counterfeiting as well.

Stimuli-responsive bio-based polymeric systems and their applications.

Stimuli-responsive bio-based polymeric systems are gaining considerable attention as intelligent versatile tools that show great potential in various fields. In this review, an overview is given of recent developments of stimuli-responsive bio-based polymeric systems. The characteristics of bio-based polymers in different applications are discussed and the superiority of these advanced stimuli-responsive bio-based polymeric systems is highlighted. Furthermore, several emerging applications of these systems including intelligent drug delivery, responsive food packaging and smart water treatment are discussed and the section of intelligent drug delivery is emphasized in detail. Finally, the respective prospects and limitations inherent to these systems are addressed.

Green electrospun and crosslinked poly(vinyl alcohol)/poly(acrylic acid) composite membranes for antibacterial effective air filtration.

Air pollution has become a major environmental concern given the ever increasing levels of particulate matter (PM) and the increased in treatment-resistant bacterial and viral strains. Major efforts are therefore required into the development of air filtration and purification technology as well as novel, alternative antiviral and antibacterial treatment modalities. Here, we report an environmentally friendly method for the generation of multifunctional poly(vinyl alcohol)/poly(acrylic acid) (PVA-PAA) composite membranes via green electrospinning and thermal crosslinking. Superhydrophobic silica nanoparticles were then incorporated into the fibers resulting in a rough surface, after which AgNO3 was introduced, resulting in the formation of Ag nanoparticles through UV reduction. The PVA-PAA-SiO2-Ag NPs membranes were found to possess high air filtration performance (with >98% filtration efficiency for PM2.5) as well as potent antibacterial and antiviral activities. The green synthesis approach avoids the use of hazardous organic solvents, thereby bypassing any potential toxicity concerns caused by organic solvent residues. These newly designed PVA-PAA-SiO2 NPs-Ag NPs nanofibrous membranes with many superior features (e.g. high filtration efficiency, high tensile strength, biological compatibility, and antibacterial properties) can be applied in eco-friendly air filtration materials, in particular for personal air filtration devices.

Synthesis and Evaluation of New Quinoxaline Derivatives of Dehydroabietic Acid as Potential Antitumor Agents.

A series of new quinoxaline derivatives of dehydroabietic acid (DAA) were designed and synthesized as potential antitumor agents. Their structures were characterized by IR, ¹H-NMR, 13C-NMR, and MS spectra and elemental analyses. All the new compounds were screened for their in vitro antiproliferative activities against three human cancer cell lines (MCF-7, SMMC-7721 and HeLa) and noncancerous human hepatocyte cells (LO2). A cytotoxic assay manifested that compound 4b showed the most potent cytotoxic activity against the three cancer cell lines, with IC50 values of 1.78 ± 0.36, 0.72 ± 0.09 and 1.08 ± 0.12 µM, respectively, and a substantially lower cytotoxicity to LO2 cells (IC50: 11.09 ± 0.57 µM). Moreover, the cell cycle analysis suggested that compound 4b caused cell cycle arrest of SMMC-7721 cells at the G0/G1 phase. In a Hoechst 33258 staining assay, compound 4b caused considerable morphological changes of the nuclei of SMMC-7721 cells, correlated with cell apoptosis. In addition, an Annexin V-FITC/PI dual staining assay confirmed that compound 4b could induce the apoptosis of SMMC-7721 cells in a dose-dependent manner.

Synthesis and in vitro cytotoxic evaluation of new 1H-benzo[d]imidazole derivatives of dehydroabietic acid.

A series of new 1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed and synthesized as potent antitumor agents. Structures of the target molecules were characterized using MS, IR, 1H NMR, 13C NMR and elemental analyses. In the in vitro cytotoxic assay, most compounds showed significant cytotoxic activities against two hepatocarcinoma cells (SMMC-7721 and HepG2) and reduced cytotoxicity against noncancerous human hepatocyte (LO2). Among them, compound 7b exhibited the best cytotoxicity against SMMC-7721 cells (IC50: 0.36±0.13µM), while 7e was most potent to HepG2 cells (IC50: 0.12±0.03µM). The cell cycle analysis indicated that compound 7b caused cell cycle arrest of SMMC-7721 cells at G2/M phase. Further, compound 7b also induced the apoptosis of SMMC-7721 cells in Annexin V-APC/7-AAD binding assay.

pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery.

In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27±2.32MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2±0.03MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for "semen sensitive" (intravaginal) drug delivery.

A novel preparation method of paclitaxcel-loaded folate-modified chitosan microparticles and in vitro evaluation.

A new chitosan microparticles loading paclitaxel (PTX) for application as an oral delivery system were developed using a novel double emulsion crosslinking method. To improve the targeted effect, folic acid (FA) was introduced onto the surface of microparticles using chemical method. The method was based on Schiff reaction between amino group of chitosan and carboxyl group of FA, and folate-chitosan (FA-CS) conjugate was characterized using infrared spectrum analysis (FT-IR), and the microparticles were named as FA-CS-PTX/MPs. FA-CS-PTX/MPs had larger size of average diameter 223.6 nm, while PTX-loaded chitosan microparticles (CS-PTX/MPs) had 179.1 nm average diameter. The zeta potential of CS-PTX/MPs and FA-CS-PTX/MPs was 22.3 and 33.1 mV, respectively. SEM and TEM showed both the two microparticles had well-defined spherical structure. The in vitro drug release was studied under different pH conditions, and a two-phase kinetics model was found to be the most adequate kinetic model. Furthermore, the cytotoxicity activities of drug-carriers against L929 cells and the cellular uptake of PTX-loaded microparticles against HepG2 cells were investigated. Results demonstrated that FA-CS-PTX/MPs might be a promising drug carrier for promoting PTX cellular uptake and could be used as a potential tumor-targeted drug vector.