Ultra-small, highly stable, and sensitive dual nanosensors for imaging intracellular oxygen and pH in cytosol.

We report on the first dual nanosensors for imaging of pH values and oxygen partial pressure in cells. The sensors have a unique nanostructure in that a soft core structure is rigidized with a silane reagent, while poly(ethylene glycol) chains form an outer shell. Lipophilic oxygen-sensitive probes and reference dyes are encapsulated inside the hydrophobic core, while a pH-sensitive probe is covalently attached to the poly(ethylene glycol) end-group on the shell. The core/shell structure renders the nanosensors well dispersed and highly stable in various kinds of aqueous media. Their average size is 12 nm, and they respond to both pH and oxygen in the physiological range. They do not pass cell membranes, but can be internalized into the cellular cytosol by electroporation, upon which they enable sensing and imaging of pH values and oxygen with high spatial resolution. The nanosensor strategy shown here is expected to be applicable to the development of various other kinds of multiple nanosensors for in vivo studies.

Clinical long-term and patient-reported outcomes of dental implants in oral cancer patients.

BACKGROUND AND PURPOSE: The aim of this clinical study was to investigate the clinical long-term and patient-reported outcome of dental implants in patients with oral cancer. In addition, analysis of the influence of radiation therapy, timing of implant insertion, and augmentation procedures on implant survival was performed. MATERIAL AND METHODS: This retrospective study investigated the clinical outcome of 711 dental implants in 164 oral cancer patients, inserted by experienced surgeons of the Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, Germany. Oral health-related quality of life (OHRQoL) was evaluated. RESULTS: Cumulative 5-year and 10-year implant survival rates for all included implants were 87.3% and 80.0%. Implants placed straight after ablative surgery (primary implant placement) and implants placed after completing the oncologic treatment (secondary implant placement) showed a comparable implant survival (92.5% vs. 89.5%; p = 0.635). Irradiation therapy had no significant influence on implant survival of secondary placed implants (p = 0.929). However, regarding implant site (native bone vs. augmented bone) and radiation therapy (non-irradiated bone vs. irradiated bone), implants inserted in irradiated bone that received augmentation procedures showed a statistically significant lower implant survival (p < 0.001). Patients reported a distinct improvement in OHRQoL. CONCLUSIONS: Promising long-term survival rates of dental implants in patients after treatment of oral cancer were seen. In addition, patients benefit in form of an improved OHRQoL. However, bone augmentation procedures in irradiated bone may result in an impaired implants' prognosis.

Tracking Hyaluronan: Molecularly Imprinted Polymer Coated Carbon Dots for Cancer Cell Targeting and Imaging.

War against cancer constantly requires new affinity tools to selectively detect, localize, and quantify biomarkers for diagnosis or prognosis. Herein, carbon nanodots (CDs), an emerging class of fluorescent nanomaterials, coupled with molecularly imprinted polymers (MIPs), are employed as a biocompatible optical imaging tool for probing cancer biomarkers. First, N-doped CDs were prepared by hydrothermal synthesis using starch as carbon source and l-tryptophan as nitrogen atom provider to achieve a high quantum yield of 25.1 ± 2%. The CDs have a typical size of ∼3.2 nm and produce an intense fluorescence at 450 nm upon excitation with UV light. A MIP shell for specific recognition of glucuronic acid (GlcA) was then synthesized around the CDs, using the emission of the CDs as an internal light source for photopolymerization. GlcA is a substructure (epitope) of hyaluronan, a biomarker for certain cancers. The biotargeting and bioimaging of hyaluronan on fixated human cervical cancer cells using CD core-MIP shell nanocomposites is demonstrated. Human keratinocytes were used as noncancerous reference cells and indeed, less staining was observed by the CD-MIP.

Studying cell-surface interactions in vitro: a survey of experimental approaches and techniques.

A better understanding of the interactions of animal (or human) cells with in vitro surfaces is the key to the successful development, improvement and optimization of biomaterials for biomedical or biotechnological purposes. State-of-the-art experimental approaches and techniques are a prerequisite for further and deeper insights into the mechanisms and processes involved in cell-surface adhesion. This chapter provides a brief but not complete survey of optical, mechanical, electrochemical and acoustic devices that are currently used to study the structural and functional properties of the cell-surface junction. Each technique is introduced with respect to the underlying principles before example data are discussed. At the end of the chapter all techniques are compared in terms of their strengths, limitations and technical requirements.

A combined prosthodontic and orthodontic treatment approach in a case of growth inhibition induced by dental implants: a case report.

Functional and esthetic results can improve significantly when a combined prosthodontic-orthodontic treatment approach is employed in cases requiring extensive oral rehabilitation. The patient presented in this case report was treated in his late teens with dental implants as a replacement for his maxillary incisors. Ten years later, the entire maxillary anterior segment was in infraocclusion compared to the rest of the dentition and lip line. Since prosthodontic follow-up treatment alone could not achieve an optimal functional and esthetic outcome, the patient was treated orthodontically prior to renewing the restoration. A fixed appliance was used to intrude the mandibular anterior teeth as well as vertically align the infrapositioned maxillary lateral incisors.

Ten-year retrospective follow-up study of the TiOblast dental implant.

PURPOSE: Long-term results in the clinical outcome of different implant systems, including high patient numbers and a long follow-up time, are rare. This retrospective study evaluated the cumulative survival rate of a self-tapping, cylindrical implant system with a conical implant-abutment connection after 10 years of prosthetic loading. MATERIALS AND METHODS: A total of 516 TiOblast implants (Astra Tech AB, Mölndal, Sweden) were placed in 108 patients. The patients were treated in the Department of Oral and Maxillofacial Surgery, Johannes Gutenberg University, Mainz, Germany, between September 1994 and May 2005. The main indications for implantation were the treatment of edentulous mandibles (74%) and partial edentulism (15%). Twenty-three implants were placed postradiation, and a further 64 implants were irradiated after insertion. In 153 implants, a bony augmentation was conducted prior to implantation. RESULTS: The in situ rate was 89.7% after an average implantation time of 108 months. Eighty-three patients with 403 implants were available for investigation. Seventeen patients with 76 implants have died since 1994. Absence of osseointegration (n = 22), peri-implantitis (n = 18), fracture of the implants (n = 9), failing of primary stability (n = 2), and implants next to tumors (n = 2) were the reasons of explantation in 26 patients. Under analysis with different implant success-assessment criteria, the success rate showed results from 76 to 89%. CONCLUSION: With respect to the critical patient selection including a high number of patients with minor and major augmentations, the 10-year clinical use of the studied implant system showed acceptable results.

Adsorption and fluctuations of giant liposomes studied by electrochemical impedance measurements.

The present study describes a novel approach based on electrochemical impedance measurements to follow the adsorption of giant liposomes on protein-coated solid surfaces with a time resolution in the order of seconds. The technical key features are circular gold-film electrodes as small as a few hundred micrometers in diameter and measurements of the electrode capacitance using AC signals in the kilohertz regime. Using Monte Carlo simulations, we were able to support the experiments and extract the rate constant of liposome adsorption. Besides monitoring the adsorption of liposomes on protein-coated surfaces, we also applied this technique to study shape fluctuations of the adsorbed vesicles and compared the corresponding power spectra with those recorded for hard particles and living animal cells.

Reconstruction of mandibular defects following tumor ablation by vertical distraction osteogenesis using intraosseous distraction devices.

OBJECTIVES: Distraction osteogenesis has recently evolved a challenging technique to overcome major drawbacks of conventional augmentation procedures. We, therefore, report the application of miniaturized intraosseous distraction devices for the rehabilitation of mandibular defects due to ablative tumor surgery. METHODS: In 10 patients who had undergone box-shaped or segmental resections, augmentation of the residual mandibular bone or of full thickness iliac crest grafts was performed by intraosseous implant-shaped distractors. Distraction and reconsolidation was monitored by ultrasonography. Implants were inserted within 1 week after active distraction. Median follow-up after implant insertion was 38 months. RESULTS: On average, a vertical gain of 7.3 mm was obtained by distraction. Except for one case (local infection), all distraction zones showed complete ossification by radiologic and ultrasonographic evaluation. Overall 28 implants were placed in the distracted bone. Two implants were lost at 2.4 and 22 months after placement. The estimated 4-year implant survival rate in this population was 90%. For the endpoint 'bone loss' (>1.5 mm in the first and >1 mm in following years), the estimated 4-year success rate was 59% with four out of seven events occurring in a single patient (patient No. 1 of this series). CONCLUSION: Vertical distraction by means of implant distractors could be performed with reasonable success in tumor patients with box-shaped resection defects or undercontoured bone grafts. Overall morbidity was very low. Even though blood supply is continuously maintained in distraction osteogenesis, bone resorption remains a critical issue for this reconstruction technique too.

Abordagem de tratamento protética e ortodôntica combinada no caso de inibição do crescimento induzida por implantes dentários: relato de caso clínico / A combined prosthodontic and orthodontic treatment approach in a case of growth inhibition induced by dental implants: a case report

Resultados estéticos e funcionais podem ser melhorados significativamente quando uma abordagem de tratamento protética e ortodôntica combinada é usada em casos que necessitam de reabilitação oral extensa. Este paciente apresentado neste relato de caso foi tratado no final de sua adolescência com implantes dentários para reposição dos incisivos superiores. Dez anos depois, todo o segmento anterior da maxila estava em infraoclusão comparado ao resto da dentição e da linha labial. Já que o acompanhamento protético em si não poderia alcançar um resultado funcional e estético adequado, a paciente foi tratada ortodonticamente antes de trocar a restauração. Um aparelho fixo foi usado para intruir os dentes anteriores inferiores e alinhar verticalmente os incisivos laterais superiores que estavam em infraposição