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This contribution underlines the key role of physicochemical characterisation techniques in the area of medical research. The starting point centres on the Mid-InfraRed platform located at the Tenon hospital and dedicated to multidisciplinary functional investigations. In the last two decades, we have enhanced this platform by creating a network combining researchers from varied disciplines such as physicists, chemists, and clinicians. The resultant research dynamism is underscored by metrics such as 71 references in Pubmed and 129 in Web of Science, and the high impact of the journals in which we have published (New England Journal of Medicine, Kidney International, Chemical Review...). It is of paramount importance to disseminate these physicochemical techniques among young doctors, and to establish collaborations with appropriate private companies.

Despite the incidence of breast cancer among women, mammography and anatomopathology investigations are still the gold standard method for preventive screening and diagnosis. Several criteria are used to diagnose precisely the severity of the pathology like the distribution and shape of breast microcalcifications (BMCs). However, the link between the different chemical phases of BMCs and the cancer stage remains unclear. As BMCs physicochemical speciation has the potential to help clinicians during their diagnosis, this study aims to propose a methodology using advanced spectroscopical analysis techniques to finely characterize BMCs and uncover the relationship between mineralization processes and breast cancer. A state of the art in the domain is first proposed to highlight the role of BMCs and the importance of extensive analytical analysis using electron microscopy and vibrational techniques. Secondly, a detailed methodology for BMCs multiscale analysis is proposed and the relevance of each technique illustrated through the study of a biopsy from a patient suffering of an infiltrating low-grade ductal carcinoma: scanning electron microscopy analysis was used for the morphological description of BMCs, infrared micro and nanospectroscopy techniques for their chemical speciation at the micrometric and sub-micrometric scales.

Morpho-constitutional analysis of gallstones revealed significant differences between sickle cell patients and other gallbladder stone formers. As expected, pigment stones, mainly composed of calcium bilirubinates, were the most common type of stones in the former (74.7 versus 22.5%, $p

This contribution is a concise review of nanomaterials in medicine, those designed to treat pathology, those which are induced by pathology, and those which provoke pathology. Clearly, there is a vast family of therapeutic and medically relevant nanomaterials, to which numerous excellent journals and books are dedicated. The purpose of the first section is to illustrate the chemical complexity of research into therapeutic nanomaterials and the challenges in their characterisation. The second section treats that family of nanomaterials induced by diverse pathologies, such as metabolic disorders, infection, or cancer. Here, the challenge is to find characterisation techniques able to provide chemical information at the nanometer scale to enable and enhance early medical diagnosis. Finally, various nanomaterials injected into the human body for esthetic purposes are discussed, specifically tattoo inks which can provoke severe pathologies such as skin cancer.

This contribution aims to define an analysis procedure for abnormal deposits in human tissues starting from in vivo characterization, down to the nanoscale using major instrumentation. Such an integrated approach is based on recent literature, but particularly on our research over the last twenty years on pathological calcifications. To this end, we begin by describing four successive analytical steps, on the injury site or physician’s surgery, at the hospital, at a typical physicochemical laboratory, and finally at a large scale (possibly multinational) facility. For the first step, we present various techniques which can be implemented on portable instruments. For the second step, commercial analytical setups are used. In a physicochemical laboratory, prototype or commercial setups are used and finally on large scale instruments, characterization techniques with better spatial resolution and/or higher sensitivity or techniques specific to synchrotron radiation are employed.

Understanding the physico-chemistry related to cristalline pathologies constitutes a challenge in several medical specialities such as nephrology, dermatology or oncology. Regarding nephrology, the chemical diversity of concretions such as kidney stones calls for characterization techniques to determine the chemical composition of concretions. The starting point of this contribution is given by Fourier Transform InfraRed (FTIR) spectroscopy which is routinely used at the hospital to determine the chemical composition of kidney stones as well as ectopic calcifications present in kidney biopsy. For kidney stones, the quantity of sample is sufficient to perform a significant analysis through classical FTIR. For ectopic calcifications, $\mu $FTIR can be inefficient in the case of $\mu $calcification in the tissue when their size is less than 10 $\mu $m. For such samples, Optical PhotoThermal IR (OPT-IR) spectroscopy may constitute a way to overcome this experimental difficulty through the acquisition of IR spectrum with a spatial resolution close to 500 nm.To illustrate such opportunity, we first compare the IR spectrum acquired with a classical experimental set-up related to classical IR spectroscopy to IR spectrum collected with a OPT-IR one for different compounds namely calcium oxalate monohydrate, calcium oxalate dehydrate, calcium phosphate apatite and magnesium ammonium phosphate hexahydrate. Such comparison helps us to assess specificity of OPT-IR. Then, we consider several pathological calcifications associated to hyperoxaluria, adenine phosphoribosyltransferase (APRT) deficiency or the presence of Randall’s plaque. We will see that the nanometer spatial resolution constitutes a major advantage versus a micrometre one. Also, in the case of Randall’s plaque, we show that OPT-IR can determine the chemical composition of microscopic concretion without any kind of preparation. Such experimental fact is clearly a major advantage. Finally, we also extended this first investigation in nephrology by considering breast calcifications. In that case, if the number of chemical phases is quite low compared to the number of chemical phases identified in ectopic calcifications present in kidney (four instead of 24), the challenge is related to the possibility to distinguish between the different calcium phosphate namely amorphous carbonated calcium phosphate, CA and whitlockite.The complete set of data indicates the limitations and the advantages of OPT-IR spectroscopy.

Epidermal necrolysis (EN) is a rare life-threatening condition, usually drug-induced and characterised by a diffuse epidermal and mucosal detachment. Calcinosis cutis is reported in various skin diseases, occurring preferentially with tissue damage, but has never been described in EN. Clinical, biological and histopathological characteristics of three patients were retrospectively obtained from medical charts. Immunohistochemistry of classical osteogenic markers was used to explore the pathogenesis of the calcifications; their chemical composition was determined by $\mu $Fourier transform infra-red ($\mu $FTIR) spectroscopy and their localization and morphology by field-emission scanning electron microscopy (FE-SEM). In a recent letter, part of the results of this investigation has been already presented. In this contribution, we have added original data to this previous letter. We have investigated a set of biopsies corresponding to patients who presented atypical healing retardation due to calcinosis cutis. Through FE-SEM observations at the nanometre scale, we describe different areas where are present voluminous calcifications at the surface, submicrometre spherical entities within the papillary dermis and then large “normal” fibres. FE-SEM observations show clearly that “large” calcifications are the result of an agglomeration of small spherical entities. Moreover, micrometre scale spherical entities are the results of an agglomeration of nanometer scale spherical entities. Finally, the last set of data seems to show that the starting point of the calcifications process is “distant” from the epidermis in part of the dermis which appears undamaged. Regarding the chemical composition of large calcifications, different $\mu $FTIR maps which underlined the presence of calcium-phosphate apatite have been gathered. Moreover, histopathology indicates that these pathological calcifications are not induced following a trans-differentiation of the skin cells into an osteochondrogenic phenotype. The association of caspofungin administration, known to induce in vitro intracellular calcium influx, and inflammation, induced by EN, known to favor dystrophic calcifications in various inflammatory skin diseases, could explain this never-before reported occurrence of calcinosis cutis.

In this contribution, we have characterized for the first time (to the best of our knowledge), microcalcifications present in fine needle aspiration (FNA) smears of thyroid nodules. Abnormal deposits were analysed through $\mu $Fourier Transform Infrared Spectroscopy ($\mu $FTIR) and Field Emission Scanning Electron Microscopy (FE-SEM) in order to obtain their chemical composition as well as their morphology at the micrometer scale. Thirty-one samples coming from 13 patients were investigated comprising five cases of papillary carcinoma, two of Graves’ disease, and six of adenomatous goitre. The smears were also stained for analysis of the cellular characteristics of these lesions for classifying according to the Bethesda classification. Two mineral species, amorphous and nanocrystallised apatite calcium phosphate, have been identified with very different morphologies. Moreover, FE-SEM observations at the micrometer scale underline the presence of different kinds of abnormal deposits.

This contribution emphasizes the chemical complexity of abnormal cartilaginous deposits. First, we briefly describe some key techniques used to precisely describe their physicochemical characteristics. Then, we present the main chemical and structural characteristics of these two chemical phases, of either biological or synthetic origins. Finally, we discuss selected examples of calcification characterization.

In this contribution, we would like to underline the peculiar chemical properties of nanometer scale metallic particles. To attain this goal, we select the case of DeNox catalysis (NOx reduction to nitrogen molecule) for which such nanomaterials play a crucial role. Experimental data as well as recent theoretical calculation through density functional theory are used to assess the relationship between the adsorption mode of NO and the behaviour of nanometre scale metallic particles.

Most papers on kidney stones arising from infection concentrate on the mineral struvite. In this contribution, we would like to call attention to other mineral phases such as highly carbonated calcium phosphate apatite, ammonium urate, and whitlockite, by presenting clinical and chemical data. We start with epidemiological data which emphasize the increase in the prevalence of kidney stones related to infection. Then we present a statistical analysis of more than 85,000 stones which have been analysed at the Laboratoire des Lithiases of Assistance Publique-Hôpitaux de Paris which gives insights regarding the link between urinary tract infection and struvite, carbonated calcium phosphate apatite (carbapatite), and also surprisingly whitlockite. Some information regarding the pathogenesis of kidney stones linked to infection, the nature of the bacteria which have been identified, and the approach to precisely analyse infrared spectra to identify struvite, carbapatite, and whitlockite, conclude this first part. To complete this clinical description, we describe the crystallographic structure and the chemistry of three relevant compounds namely carbonated calcium phosphate, struvite, and whitlockite. To conclude this second part, the dependence of crystallite morphology of struvite on pH and on the presence, or absence, of bacteria, is described. Based on clinical and chemical data, it is becoming clear that struvite is not the only mineral intimately related to renal infectious processes, but that whitlockite and carbapatite with a high carbonation rate are strongly associated with urinary tract infection as well.

X-ray Photoelectron Spectroscopy (XPS) constitutes an elegant way to describe the chemical characteristics of the surface of biological materials. It is thus a unique approach to decipher the interaction between biological materials and tissues. In the case of medical implants, it is thus possible to understand its biocompatibility as well as its integration in the body which can be wanted in the case of prothesis or avoided in the case of JJ-stents. More precisely, XPS can bring valuable information of the interaction between physiological calcification (here bone) and the prosthesis as well as the interaction between pathological calcifications (lithiasis) and the JJ-stent. This mini overview is dedicated to two communities, the physical chemists and the clinicians. In the first part of this overview, after an introduction on the basic principles of XPS, we focus on the theoretical techniques adopted for the computation of XPS spectra of materials.The second part, dedicated to clinicians, describes the use of XPS for the characterization of biological materials. We report which kind of chemical information can be gained by this surface-sensitive technique and how this information has a relevant impact on medical applications.Through different examples, we show that XPS is a strong and very useful tool, and thus receiving a crucial place in medical research.

Although numerous pathologies are associated with abnormal skin deposits, these remain poorly described, as accurate characterization continues to present a challenge for dermatologists. Their submicrometer size as well as their diverse chemistry require various characterization tools. We aim to exemplify characterization of endogenous and exogenous skin deposits in some selected skin diseases using different physico-chemical techniques. We begin with a presentation of selected diseases associated with skin deposits. We then present those of our results which show their variety of structure, location and chemical composition, obtained with various tools: Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy, X-ray fluorescence, vibrational spectroscopies, as well as techniques specific to synchrotron radiation. Our results constitute a real opportunity to improve diagnosis, and to understand the pathogenesis of many skin diseases, and opportunities for therapeutic intervention.

Here is a case of bladder stone of average size dated to the Late Neolithic period, found in the multiple burial of the B1S passage-grave in Chenon (Charente, France). Chemical analysis showed a mixed composition. The core, intermediate and surface envelopes consist in calcium phosphate apatite associated with whitlockite and amorphous carbonated calcium phosphate, all clarified by Fourier Transform InfraRed spectroscopy. Calcium phosphatic stones are characteristic of communities, such as those of the Neolithic period, where the diet was rich in cereal carbohydrates and poor in animal proteins. The excavation of such extra-skeletal objects is an event that is particularly interesting as it provides documents on the history of diseases and diets in ancient populations. The complete set of data suggests that this bladder stone was formed during a urinary tract infection with a germ possessing a very active urease.

Medical literature indicates clearly that cystinuria and cystinosis, two severe genetic pathologies, are related to the presence of abnormal L-cystine deposits. While L-cystine adopts a hexagonal crystal morphology consistent with its crystallographic structure (hexagonal, $\mathrm{P}6_{1}22$ space group), abnormal deposits related to cystinosis display a rectangular shape. Because this is unexpected from the hexagonal crystallographic structure of L-cystine, we have investigated this inconsistency using SEM (scanning electron microscopy) and IR (infrared) spectroscopy at micrometre and nanometre scales. Our data clearly indicate the presence of both L-cysteine and L-cystine. Considering that L-cysteine crystals display a rectangular shape, and that a transition phase between L-cysteine and L-cystine is well known, we propose the following model for deposit evolution in cystinosis. The initial abnormal deposit consists of L-cysteine, with a rectangular crystal morphology. The micrometre scale rectangular crystallite shape is retained after the phase transition equilibrium between L-cysteine and L-cystine is established, with some crystalline L-cysteine still remaining.

Medullary sponge kidney (MSK) is an anomaly of the kidney with cystic enlargement of distal tubules generating stasis zones where calcium salt deposits may form and grow locally. From an epidemiological point of view, MSK is reported in 2% to more than 20% of calcium stone formers. The association of stasis and various metabolic disorders explains a high recurrence rate of stones in affected patients. The composition of stones has been poorly investigated. The aim of this study is to compare stone composition and morphology in MSK and non-MSK patients.Material and methods: 1036 stones from MSK patients and 31,494 stones from non-MSK patients were submitted to a morpho-constitutional analysis based on morphological typing under stereo microscope and precise characterization of chemical and crystalline phases by Fourier transform infrared spectroscopy.Results and discussion: Regarding patients, the male to female ratio was significantly lower in MSK vs non-MSK subjects (1.48 vs 2.09, $p

The calcareous skeletons built by invertebrate organisms share a paradoxical property. Although growing outside the mineralizing cell layers the crystal-like skeleton units exhibit morphologies and three-dimensional arrangements that imply an efficient link between crystallization process and taxonomy. Almost two centuries of investigation led to a series of developmental models in which biological and physical or chemical influences are variously balanced. Recent innovative methods allow for their re-examination. From control of the overall shape of the shell to photo-spectroscopic evidence at the atomic level, influence of the biological processes on mineral properties may be a widely shared specificity of the calcareous biomineralization mechanism.

XANES spectroscopy, which uses synchrotron radiation as a probe, offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate. Its subcellular spatial resolution, as well as its capacity to operate at room temperatures and pressures represent major advantages for medical research. Moreover, paraffin embedded biopsy samples can be analysed without any further preparation, Key publications which illustrate these capacities are presented.

The aim of this contribution is to present to the community the very unique diagnostic capabilities of Raman spectroscopy in the context of pathological calcifications. By offering the clinician the opportunity to determine within seconds the chemical composition of micron-sized crystallites, possibly in vivo, Raman analyses find no equivalent among the large set of analytical tools available. After a brief recap of some peculiar aspects of this spectrometry and a presentation of the latest instrumental developments, this review gathers the most recent literature on the use of Raman to diagnose various lithiases or microcrystalline pathologies.

Since its first use several decades ago, scanning electron microscopy has been used in numerous investigations dedicated to biological systems. This contribution focuses on observations on pathological calcifications in order to review several major applications of primary importance to the clinician. Among these, we highlight such observations as medical diagnostic tools in pathologies arising from primary hyperoxaluria and urinary infections.

Adenine phosphoribosyltransferase (APRT) deficiency is a genetic disease characterized by an increased production of 2,8 dihydroxyadenine (2,8-DHA) precipitating in urine, leading to a crystalline nephropathy and end-stage renal disease. Here, we describe the high prevalence of granuloma (88%) in biopsies from patients with APRT deficiency. A murine model of 2,8-DHA nephropathy was generated, showing that anakinra or dexamethasone, combined with allopurinol, improved renal function to a larger extent than allopurinol alone, the standard therapy. Inflammation plays a critical role in the development of 2,8-DHA nephropathy, and therapy based upon drugs targeting innate immunity could improve renal function recovery.

This contribution tries to indicate to the clinician what kind of information can be investigated through X-ray fluorescence, what kind of information can be extracted from this spectroscopy and finally how it competes with other tools described in previous publications such as Fourier Transform Infrared or Raman spectroscopy, X-ray Absorption Near Edge Structure spectroscopy and X-ray diffraction. To attain this goal, several examples based on X-ray fluorescence experiments performed on biological samples namely concretions, medical devices, biological fluids as well as tissues are presented.

The majority of idiopathic calcium oxalate kidney stones form on the Randall’s plaque, a subepithelial calcium phosphate plaque at the renal papilla. The formation mechanisms of the Randall’s plaque and associated calcium oxalate stones remain incompletely understood. This article provides an historical overview of the research performed on this topic, describes the current epidemiological trends of Randall’s plaque-associated kidney stone formation and reviews the suggested formation mechanisms of Randall’s plaque and associated calcium oxalate stones. Finally, this overview highlights the recent advances made on the subject, including the development of an animal model.

Chemical composition is not the only information establishing a significant link between kidney stones and the pathology which induces urolithiasis. Structural parameters such as morphology and crystal and crystallite size are also of primary importance. In this contribution, we would like to assess the relationship of crystal size of different chemical phases with the pathology underlying such calcifications. Based on literature as well as on some of our measurements, we will appreciate the value of this structural parameter for different crystalline species in various clinical or biological conditions and in helping the clinician, especially to understand why bacterial imprints in infection-related stones are only visible in calcium phosphate apatite deposits.

Density Functional Theory has made the study of biomaterials feasible in the past years leading to better understanding of causes and possible treatments of related pathologies. Although it has been successfully applied in many fields, it has not yet consistently found its way into the field of pathological calcifications. An overview will be given of the studies where this technique has been applied in order to outline the important contributions that it can bring in the field of biomineralization. More specifically, studies on DFT calcifications from calcium oxalates and calcium phosphates, with relevance to bone formation and kidney stones, will be reviewed. Finally, a short outlook on silica mineralization will be presented as well.

Stone analysis is a critical part of the clinical characterization of urolithiasis. This article reviews the strengths and limitations of micro CT in the analysis of stones. Using micro CT alone in a series of 757 stone specimens, micro CT identified the 458 majority calcium oxalate specimens with a sensitivity of 99.6% and specificity of 95.3%. Micro CT alone was also successful in identifying majority apatite, brushite, uric acid, and struvite stones. For some minor minerals—such as apatite in calcium oxalate or calcium salts in uric acid stones—micro CT enables the detection of minute quantities well below 1%. The addition of a standard for calibrating X-ray attenuation values improves the ability of micro CT to identify common stone minerals. The three-dimensional nature of micro CT also allows for the visualization of surface features in stones, which is valuable for the study of stone formation.

In this contribution dedicated to kidney stones containing Whitlockite (Wk), we addressed three questions, namely, the presence of iron in Wk, the relationship between bacterial imprints and the presence of Wk, and finally the relationship between the crystal size of Wk-bearing stones and infection. The complete dataset indicates that iron is not present in our Wk stoichiometry. We also note the presence of bacterial imprints for kidney stones with a high, but sometimes a low content, of Wk. Finally, we propose FE-SEM as a diagnostic tool for stone patients who have a negative urine culture associated with kidney stones containing less than 20% by weight Wk, a low level of carbonate in apatite, and no struvite. Such a diagnostic tool would represent a significant benefit to the clinician.

Background: Markers of exposure to environmental toxicants are urgently needed. Tooth enamel, with its unique properties, is able to record certain environmental conditions during its formation. Enamel formation and quality are dependent on hormonal regulation and environmental conditions, including exposure to endocrine disrupting chemicals (EDCs). Among EDCs, phthalates such as di-(2-ethylhexyl) phthalate (DEHP) raise concerns about their contribution to various pathologies, including those of mineralized tissues. Objectives: The effects of exposure to low-doses of DEHP on the continually growing incisors were analyzed in mouse males and females. Methods: Adult male and female C57BL/6J mice were exposed daily to 0.5, 5, and 50 [micro]g/kg per day DEHP for 12 wk and their incisors clinically examined. Incisors of males were further analyzed by scanning electron microscopy (SEM), micro X-ray computed tomography (micro-computed tomography; [micro]CT), and nanoindentation for the enamel, histology and real-time quantitative polymerase chain reaction (RT-qPCR) for the dental epithelium. Results: Clinical macroscopic observations of incisors showed various dose-dependent dental lesions such as opacities, scratches, and enamel breakdown in 30.5% of males (10 of 34 total incisors across three independent experiments), and 15.6% of females (7 of 46 incisors) at the highest dose, among which 18.1% (6 of 34 total incisors across three independent experiments) and 8.9% (4 of 46 incisors), respectively, had broken incisors. SEM showed an altered enamel surface and ultrastructure in DEHP-exposed male mice. Further characterization of the enamel defects in males by [micro]CT showed a lower mineral density than controls, and nanoindentation showed a lower enamel hardness during all stages of enamel mineralization, with more pronounced alterations in the external part of the enamel. A delay in enamel mineralization was shown by several approaches ([micro]CT, histology, and RT-qPCR). Discussion: We conclude that DEHP disrupted enamel development in mice by directly acting on dental cells with higher prevalence and severity in males than in females. The time window of DEHP effects on mouse tooth development led to typical alterations of structural, biochemical, and mechanical properties of enamel comparable to other EDCs, such as bisphenol A. The future characterization of dental defects in humans and animals due to environmental toxicants might be helpful in proposing them as early markers of exposure to such molecules. https://doi.org/10.1289/EHP10208, Introduction The environment is continually evolving, with considerable changes in recent decades that have had an impact on human health and well-being, as well as all living organisms. (1-4) Markers [...]

This article focuses on the atomic force microscopy-infrared (AFM-IR) technique and its recent technological developments. Based on the detection of the photothermal sample expansion signal, AFM-IR combines the high spatial resolution of atomic force microscopy with the chemical identification capability of infrared spectroscopy to achieve submicrometric physico-chemical analyses. Since the first publication in 2005, technological improvements have dramatically advanced the capabilities of AFM-IR in terms of spatial and spectral resolution, sensitivity, and fields of applications. The goal of this paper is to provide an overview of these developments and ongoing limitations. We summarize recent progress in AFM-IR implementations based on the major AFM contact, tapping, and peak force tapping modes. Additionally, three new trends are presented, namely, AFM-IR applied to mineral samples, in fluid and a novel, purely surface sensitive AFM-IR configuration, to probe top layers. These trends demonstrate the immense potential of the technique and offer a good insight into the scope of AFM-IR. [ABSTRACT FROM AUTHOR]