Michael To

Modulation of collagen alignment by silver nanoparticles results in better mechanical properties in wound healing

UNLABELLED Our previous study has revealed that silver nanoparticles (AgNPs) have potential to promote wound healing by accelerated re-epithelization and enhanced differentiation of fibroblasts. However, the effect of AgNPs on the functionality of repaired skin is unknown. The aim of this study was to explore the tensile properties of healed skin after treatment with AgNPs. Immunohistochemical staining, quantitative assay and scanning electron microscopy (SEM) were used to detect and compare collagen deposition, and the morphology and distribution of collagen fibers. Our results showed that AgNPs improved tensile properties and led to better fibril alignments in repaired skin, with a close resemblance to normal skin. Based on our findings, we concluded that AgNPs were predominantly responsible for regulating deposition of collagen and their use resulted in excellent alignment in the wound healing process. The exact signaling pathway by which AgNPs affect collagen regeneration is yet to be investigated. FROM THE CLINICAL EDITOR The aim of this study was to explore the tensile properties of healed skin after treatment with AgNPs. These nanoparticles improved tensile properties and led to better fibril alignments in repaired skin, with a close resemblance to normal skin. The exact signaling pathway by which AgNPs affect collagen regeneration is yet to be investigated.

Droplet based microfluidic fabrication of designer microparticles for encapsulation applications

Developing carriers of active ingredients with pre-determined release kinetics is a main challenge in the field of controlled release. In this work, we fabricate designer microparticles as carriers of active ingredients using droplet microfluidics. We show that monodisperse droplet templates do not necessarily produce monodisperse particles. Magnetic stirring, which is often used to enhance the droplet solidification rate, can promote breakup of the resultant microparticles into fragments; with an increase in the stirring time, microparticles become smaller in average size and more irregular in shape. Thus, the droplet solidification conditions affect the size, size distribution and morphology of the fabricated particles, and these attributes of the microparticles strongly influence their release kinetics. The smaller the average size of the microparticles is, the higher the initial release rate is. The release kinetics of drug carriers is strongly related to their characteristics. The understanding of this relationship enables the fabrication of tailor-designed carriers with a specified release rate, and even programmed release to meet the needs of applications that require a complex release profile of the active ingredients.

Atypical femoral diaphyseal and subtrochanteric fractures and their association with bisphosphonates

Antiresorptive bisphosphonate agents are the mainstay of treatment for osteoporosis in both men and postmenopausal women. However, recent studies have raised concerns about the oversuppression of bone turnover related to the long-term use of bisphosphonates. Cases of atypical femoral diaphyseal and subtrochanteric fracture were reported recently in patients on long-term alendronate, and oversuppression of bone turnover was postulated to be the cause. We retrospectively reviewed all patients with femoral diaphyseal and subtrochanteric fracture presented between July 2003 and June 2008, and identified 10 patients who reported prior bisphosphonate use. Bone formation markers of all these patients were in the low range. Although the incidence of bisphosphonate-related atypical fracture accounts for an extremely low percentage of the total number of femoral diaphyseal and subtrochanteric fractures, we observed a steady increase from 0% in 2003 to 2004 to 25% in 2007 to 2008.

Hereditary multiple exostoses of the hip

Purpose. To assess the radiographic features of 36 hips with hereditary multiple exostoses (HME). Methods. Hip parameters of 12 males and 6 females (36 hips) aged 2 to 28 years with HME were assessed using anteroposterior radiographs. The recorded features included the sites of osteochondromas, the femoral head/neck ratio, the Reimers migration percentage, Sharps acetabular angle, the centre edge angle, the femoral neck-shaft angle, and degenerative changes. Results. 15 of the 18 patients were asymptomatic; 3 complained of pain (2 underwent excision or bone biopsy); no lesion was malignant. Osteochondromas were most commonly located in the femur followed by the ilium; only one was intra-articular. 32 hips had coxa valga; 26 had an abnormal Reimers migration percentage; 17 had an abnormal Sharps acetabular angle; 12 had an abnormal centre edge angle; 32 had an abnormal femoral neck-shaft angle; and 6 had degenerative changes. Acetabular and femoral dysplasia as well as subluxation are common in patients with HME. Conclusion. Borderline subluxated hips and those with marked coxa valga and/or acetabular dysplasia should be closely monitored to determine the need for surgery in the future. Subluxated hips should be operated on early, particularly in children and symptomatic adults.

Silver nanoparticles alter proteoglycan expression in the promotion of tendon repair

This study demonstrates a novel method of using silver nanoparticles for Achilles tendon injury healing. In vitro results indicated a stimulatory effect on cell proliferation and collagen synthesis with silver nanoparticles. Biomechanical test on the 42-day post operation Achilles tendon sample exhibited a significant improvement in tensile modulus when compared to the untreated group. Histology suggested that silver nanoparticles promoted cell alignment and proteoglycan synthesis. The collagen deposition was also improved. An alleviation of tumor necrosis factor α, and an increase in fibromodulin and proliferating cell nuclear antigen expression were seen in silver nanoparticles group by immunohistochemistry. This study further corroborates the finding of our previous study that silver nanoparticles help to restore the functionality of injured connective tissues. We believe that the anti-inflammatory nature of silver nanoparticles has an important role in accelerating the healing process and reducing scarring, leading to better functional outcome. From the clinical editor: Tendon healing after surgeries remains a slow and tedious process, typically requiring several weeks of recovery time and gradual introduction of physical therapy. There are no currently utilized methods that could promote tendon healing. In this study, silver nanoparticles are reported to facilitate Achilles tendon repair in a model system, through increased proteoglycan and collagen synthesis, paving the way to potential clinical applications in the future.

Development of novel implants with self-antibacterial performance through in-situ growth of 1D ZnO nanowire

To prevent the attachment of bacteria to implant surfaces, the 1D zinc oxide nanowire-coating has been successfully developed on material surfaces by using a custom-made hydrothermal approach. The chemical nature, surface topography and wettability of spike-like 1D ZnO nanowire-coating are comprehensively investigated. The anti-adhesive and antimicrobial properties of 1D nanowire-coating are tested against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli by using in vitro live/dead staining and scanning electron microscopy. We find that the adhesion of bacteria can be reduced via the special spike-like topography and that the release of Zn(2+) ions can help suppress the growth of attached bacteria. Furthermore, the antimicrobial effect is also evaluated under in vivo conditions by using a rat model infected with bioluminescent S. aureus. The amount of live bacteria in the rat implanted with a nanowire-coated sample is less than that of the control at various time points. Hence, it is believed that the nanowire-coated material is promising for application in orthopaedic implantation after the long-term animal studies have been completed.

Septic arthritis caused by Brucella melitensis in urban Shenzhen, China: a case report.

IntroductionBrucellosis is a systemic infectious disease which is still a challenging medical problem in rural areas such as northern China. It rarely occurs in urban areas such as Shenzhen in southern China. Osteoarticular involvements are frequently seen in brucellosis, and rarely is arthritis the only clinical presentation. We report a case of hip septic arthritis caused by Brucella melitensis in an urban area of Shenzhen, China.Case presentationA 29-year-old Chinese woman, Han ethnical group presented to our hospital with left hip pain persisting for one month. She had a history of contact with goats one month before admission. Her clinical examination showed marked tenderness and limited movement of her left hip. Further imaging showed effusion of her left hip joint. Inflammatory markers including erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) were raised. Our clinical diagnosis was septic arthritis of the left hip. A left hip arthroscopy was performed and the culture was positive for Brucella melitensis. She returned to normal activity after completing a standard antibiotic regimen, including gentamicin at 120mg daily for 2 weeks, doxycycline at 100mg daily and rifampicin at 450mg for a total of 12 weeks.ConclusionsBrucellosis is endemic in some rural areas of China, but rare in urban areas such as Shenzhen in southern China. However, more cases will be expected in urban areas due to increasing migration within China. Physicians should consider brucellosis as one of the differential diagnosis of arthritis. Early surgical intervention is recommended to prevent further joint destruction.

The use of three-dimensional printing technology in orthopaedic surgery: A review

Three-dimensional (3-D) printing or additive manufacturing, an advanced technology that 3-D physical models are created, has been wildly applied in medical industries, including cardiothoracic surgery, cranio-maxillo-facial surgery and orthopaedic surgery. The physical models made by 3-D printing technology give surgeons a realistic impression of complex structures, allowing surgical planning and simulation before operations. In orthopaedic surgery, this technique is mainly applied in surgical planning especially revision and reconstructive surgeries, making patient-specific instruments or implants, and bone tissue engineering. This article reviews this technology and its application in orthopaedic surgery.

Genitopatellar syndrome: a case report of a rare entity with 11 years of follow-up.

Genitopatellar syndrome is one of the syndromes described in the last decade. It is characterized by agenesis of the corpus callosum, absent or hypoplastic patellae, extremity contractures, skeletal anomalies, urogenital anomalies, and facial dysmorphic features. While writing this report, only 15 cases have been reported in the literature. The etiology, clinical features, management, and natural history of this syndrome are not yet well established. Past reports in the literature have not been able to identify the exact genetic etiology but it somewhat coincides with nail patella syndrome and short patella syndrome. We would like to introduce this terminology to the orthopedic community and highlight the clinical features of the genitopatellar syndrome. To the best of our knowledge, this is a single case report with the longest follow-up of 11 years in the literature.

Interfacial Fast Release Layer in Monodisperse Poly (Lactic-Co-Glycolic Acid) Microspheres Accelerates the Drug Release

Understanding microstructural evolutions of drug delivery devices during drug release process is essential for revealing the drug release mechanisms and controlling the drug release profiles. In this study, monodisperse poly (lactic-co-glycolic acid) microspheres in different diameters were fabricated by microfluidics in order to find out the relationships between the microstructural evolutions and the drug release profiles. It was found that poly (lactic-co-glycolic acid) microspheres underwent significant size expansion which took place from the periphery to the center, resulting in the formation of interfacial fast release layers. At the same time, inner pores were created and the diffusion rate was increased so that the early stage drug release was accelerated. Due to the different expansion rates, small poly (lactic-co-glycolic acid) microspheres tendered to follow homogeneous drug release while large poly (lactic-co-glycolic acid) microspheres tendered to follow heterogeneous drug release. This study suggests that the size expansion and the occurrence of interfacial fast release layer were important mechanisms for early stage drug release of poly (lactic-co-glycolic acid) microspheres.