Self-propelled microjet engines (microbots) can transport multiple cells into specific locations in a fluid. The motion is externally controlled by a magnetic field which allows to selectively load, transport and deliver the cells.

We report a method for the precise capturing of embryonic fibroblast mouse cells into rolled-up microtube resonators. The microtubes contain a nanometer-sized gap in their wall which defines a new type of optofluidic sensor, i.e., a flexible split-wall microtube resonator sensor, employed as a label-free fully integrative detection tool for individual cells. The sensor action works through peak sharpening and spectral shifts of whispering gallery modes within the microresonators under light illumination.

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Arrays of transparent rolled‐up microtubes can easily be mass‐produced using a combination of conventional photolithography, electron beam depositioning, and chemical etching techniques. Here, we culture primary mouse motor neurons and immortalised CAD cells, a cell line derived from the central nervous system, on various microtube substrates to investigate the influence of topographical surface features on the growth and differentiation behaviour of these cells. Our results indicate that the microtube chips not only support growth of both cell types but also provide a well‐defined, geometrically confined 3D cell culture scaffold. Strikingly, our micropatterns act as a platform for axon guidance with protruding cell extensions aligning in the direction of the microtubes and forming complex square‐shaped grid‐like neurite networks. Our experiments open up a cost‐efficient and bio‐compatible way of analysing single cell behaviour in the context of advanced micro‐/nanostructures with various biological applications ranging from neurite protection studies to cell sensor development.

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There is increasing demand for efficient and physiological in vitro cell culture systems suitable for testing new pharmaceutical drugs or for evaluating materials for tissue regeneration. In particular, co-cultures of two or more tissue-relevant cell types have the advantage to study the response of cells on diverse parameters in a more natural environment with respect to physiological complexity. We developed a direct bone cell co-culture system using human peripheral blood monocytes (hPBMC) and human bone marrow stromal cells (hBMSC) as osteoclast/osteoblast precursor cells, respectively, strictly avoiding external supplements for the induction of differentiation. The sophisticated direct hPBMC/hBMSC co-culture was characterized focusing on osteoclast function and was compared with two indirect approaches. Only in the direct co-culture, hPBMC were triggered by hBMSC into osteoclastogenesis and became active resorbing osteoclasts. Bisphosphonates and sulfated glycosaminoglycans were used to examine the suitability of the co-culture system for evaluating the influence of certain effectors on bone healing and bone regeneration and the contribution of each cell type thereby. The results show that the investigated substances had more pronounced effects on both osteoblasts and osteoclasts in the co-culture system than in respective monocultures.

Bone defects of critical size after compound fractures, infections, or tumor resections are a challenge in treatment. Particularly, this applies to bone defects in patients with impaired bone healing due to frequently occurring metabolic diseases (above all diabetes mellitus and osteoporosis), chronic inflammation, and cancer. Adjuvant therapeutic agents such as recombinant growth factors, lipid mediators, antibiotics, antiphlogistics, and proangiogenics as well as other promising anti-resorptive and anabolic molecules contribute to improving bone healing in these disorders, especially when they are released in a targeted and controlled manner during crucial bone healing phases. In this regard, the development of smart biocompatible and biostable polymers such as implant coatings, scaffolds, or particle-based materials for drug release is crucial. Innovative chemical, physico- and biochemical approaches for controlled tailor-made degradation or the stimulus-responsive release of substances from these materials, and more, are advantageous. In this review, we discuss current developments, progress, but also pitfalls and setbacks of such approaches in supporting or controlling bone healing. The focus is on the critical evaluation of recent preclinical studies investigating different carrier systems, dual- or co-delivery systems as well as triggered- or targeted delivery systems for release of a panoply of drugs.

Pilonidal disease is a debilitating, chronic disease of the natal cleft. It mainly involves the sacrococcygeal region and the presentation varies from asymptomatic pits to painful draining abscesses. Treatment options vary from observation to wide excision. Unfortunately, surgical treatment often results in recurrence. The etiologic agent remains in question, as does the optimal treatment. Our objective was to assess the efficacy of laser epilation as an adjunctive therapy to surgical excision of the pilonidal sinus. Eighteen men and five women were treated with laser epilation in our office from 2001 to 2004. All patients had experienced recurrent folliculitis and had undergone some form of drainage procedure or prior excision. After surgical excision of the affected area, a Vasculite™ Plus laser was used for the epilation treatments. Each session involved 9 to 12 treatments and the patients underwent an average of two sessions. All 19 of the patients that remain in follow-up report no recurrence of their folliculitis or need for further surgical procedures. During treatment, six of the men and one of the women experienced a superficial wound dehiscence. All healed with local wound care and continued laser treatments. Laser epilation is an effective adjunctive therapy for the treatment of pilonidal disease. Although not curative in and of itself, the removal of hair allows better healing and decreases the chance of recurrence by removal of a significant etiology of pilonidal disease.