Commercially Relevant Orthogonal Multi-Component Supramolecular Hydrogels for Programmed Cell Growth.

This study reports the ability of synthetically simple, commercially viable sugar-derived 1,3:2,4-dibenzylidenesorbitol-4',4"-diacylhydrazide (DBS-CONHNH2 ) to support cell growth. Simple mixing and orthogonal self-sorting can formulate heparin, agarose, and heparin-binding micelles into these gels-easily incorporating additional function. Interestingly, the components used in the gel formulation, direct the ability of cells to grow, meaning the chemical programming of these multi-component gels is directly translated to the biological systems in contact with them. This simple approach has potential for future development in regenerative medicine.

1,3:2,4-Dibenzylidene-D-sorbitol (DBS) and its derivatives--efficient, versatile and industrially-relevant low-molecular-weight gelators with over 100 years of history and a bright future.

Dibenzylidene-D-sorbitol (DBS) has been a well-known low-molecular-weight gelator of organic solvents for over 100 years. As such, it constitutes a very early example of a supramolecular gel--a research field which has recently developed into one of intense interest. The ability of DBS to self-assemble into sample-spanning networks in numerous solvents is predicated upon its 'butterfly-like' structure, whereby the benzylidene groups constitute the 'wings' and the sorbitol backbone the 'body'--the two parts representing the molecular recognition motifs underpinning its gelation mechanism, with the nature of solvent playing a key role in controlling the precise assembly mode. This gelator has found widespread applications in areas as diverse as personal care products and polymer nucleation/clarification, and has considerable potential in applications such as dental composites, energy technology and liquid crystalline materials. Some derivatives of DBS have also been reported which offer the potential to expand the scope and range of applications of this family of gelators and endow the nansocale network with additional functionality. This review aims to explain current trends in DBS research, and provide insight into how by combining a long history of application, with modern methods of derivatisation and analysis, the future for this family of gelators is bright, with an increasing number of high-tech applications, from environmental remediation to tissue engineering, being within reach.

Non-melanoma skin cancers: physio-pathology and role of lipid delivery systems in new chemotherapeutic treatments.

Non-melanoma carcinoma has high incidence rates and has two most common subtypes: basal cell carcinoma and squamous cell carcinoma. This type of carcinoma is usually not fatal; however, it can destroy sensory organs such as the nose, ears, and lips. The treatment of these injuries using non-invasive methods is thus strongly recommended. Some treatments for non-melanoma carcinoma are already well defined, such as surgery, cryosurgery, curettage and electrode section, and radiotherapy; however, these conventional treatments cause inflammation and scarring. In the non-surgical treatment of non-melanoma carcinoma, the topical administration of chemotherapeutic drugs contributes for an effective treatment with reduced side effects. However, the penetration of anticancer drugs in the deeper layers of the skin is required. Lipid delivery systems (liposomes, solid lipid nanoparticles, nanostructured lipid carriers) have been developed to overcome epidermal barrier of the skin and to allow the drugs to reach tumor cells. These lipid nanoparticles contribute to control the release profile of the loaded chemotherapeutic drugs, maintaining their stability and increasing death of tumor cells. In this review, the characteristics of non-melanoma carcinoma will be discussed, describing the main existing treatments, together with the contribution of lipid delivery systems as an innovative approach to increase the effectiveness of topical therapies for non-melanoma carcinomas.

Effect of buffer at nanoscale molecular recognition interfaces - electrostatic binding of biological polyanions.

We investigate the impact of an over-looked component on molecular recognition in water-buffer. The binding of a cationic dye to biological polyanion heparin is shown by isothermal calorimetry to depend on buffer (Tris-HCl > HEPES > PBS). The heparin binding of self-assembled multivalent (SAMul) cationic micelles is even more buffer dependent. Multivalent electrostatic molecular recognition is buffer dependent as a result of competitive interactions between the cationic binding interface and anions present in the buffer.

Quantitative transportation assessment in curved canals prepared with an off-centered rectangular design system.

The purpose of this study was to assess the ability of an off-centered rectangular design system [ProTaper Next (PTN)] to maintain the original profile of the root canal anatomy. To this end, ProTaper Universal (PTU), Reciproc (R) and WaveOne (WO) systems were used as reference techniques for comparison. Forty clear resin blocks with simulated curved root canals were randomly assigned to 4 groups (n = 10) according to the instrumentation system used: PTN, PTU, R and WO. Color stereomicroscopic images of each block were taken before and after instrumentation. All image processing and data analysis were performed with an open source program (Fiji v.1.47n). Evaluation of canal transportation was obtained for two independent regions: straight and curved portions. Univariate analysis of variance and Tukey's Honestly Significant Difference test were performed, and a cut-off for significance was set at α = 5%. Instrumentation systems significantly influenced canal transportation (p = 0.000). Overall, R induced significantly lower canal transportation compared with WO, PTN and PTU (p = 0.000). The curved portion displayed superior canal transportation compared to the straight one (p = 0.000). The significance of the difference among instrumentation systems varied according to the canal level evaluated (p = 0.000). In its straight portion, R and WO exhibited significantly lower transportation than PTN; whereas in the curved portion, R produced the lowest deviation. PTU exhibited the highest canal transportation at both levels. It can be concluded that PTN produced less canal transportation than PTU and WO; however, R exhibited better centering ability than PTN.

Quantitative transportation assessment in curved canals prepared with an off-centered rectangular design system

Abstract The purpose of this study was to assess the ability of an off-centered rectangular design system [ProTaper Next (PTN)] to maintain the original profile of the root canal anatomy. To this end, ProTaper Universal (PTU), Reciproc (R) and WaveOne (WO) systems were used as reference techniques for comparison. Forty clear resin blocks with simulated curved root canals were randomly assigned to 4 groups (n = 10) according to the instrumentation system used: PTN, PTU, R and WO. Color stereomicroscopic images of each block were taken before and after instrumentation. All image processing and data analysis were performed with an open source program (Fiji v.1.47n). Evaluation of canal transportation was obtained for two independent regions: straight and curved portions. Univariate analysis of variance and Tukey's Honestly Significant Difference test were performed, and a cut-off for significance was set at α = 5%. Instrumentation systems significantly influenced canal transportation (p = 0.000). Overall, R induced significantly lower canal transportation compared with WO, PTN and PTU (p = 0.000). The curved portion displayed superior canal transportation compared to the straight one (p = 0.000). The significance of the difference among instrumentation systems varied according to the canal level evaluated (p = 0.000). In its straight portion, R and WO exhibited significantly lower transportation than PTN; whereas in the curved portion, R produced the lowest deviation. PTU exhibited the highest canal transportation at both levels. It can be concluded that PTN produced less canal transportation than PTU and WO; however, R exhibited better centering ability than PTN.

Quantitative transportation assessment in simulated curved canals after large apical preparations

Aim: To evaluate the ability of rotary (ProTaper Universal [PTU] and ProTaper Next [PTN]), reciprocating (Reciproc [R] and WaveOne [WO]) and adaptive (Twisted File Adaptive [TFA]) systems in maintaining the original canal profile in straight and curved parts after apical preparations up to size 40. Methods: Resin blocks with simulated curved canals were randomly assigned to five groups: PTU, PTN, R, WO and TFA. Images were captured from each block before and after canal preparation (n=10). Assessment of canal transportation was obtained for the straight and curved parts of the canal. ANOVA followed by Tukey's test was used (α = 5%). Results: Transportation values were increased at the curved part (P = .00). For both canal levels, TFA system induced the lowest mean of canal transportation followed by PTN, R, WO and PTU systems. At the straight portion, transportation for R and TFA systems were similar (P > .05), and these values were significantly lower than for WO, PTN and PTU (P = .00). At the curved portion, TFA resulted in less canal transportation, followed by PTN, R, WO and PTU systems (P = .00). Conclusions: TFA system produced less canal transportation than other systems tested during large apical preparations. (AU)