ORIGINAL ARTICLE Raman spectroscopic study of the repair of surgical bone defects grafted or not with biphasic synthetic micro-granular HA + β-calcium triphosphate irradiated or not with λ850 nm LED light Luiz Guilherme P. Soares & Aparecida Maria C. Marques & Milena G. Guarda & Jouber Mateus S. Aciole & Aline S. Andrade & Antonio Luiz B. Pinheiro & Landulfo Silveira Jr. Received: 22 May 2013 /Accepted: 28 May 2014 # Springer-Verlag London 2014 Abstract The handling of bone losses due to different etio- logic factors is difficult and many techniques are aim to improve repair, including a wide range of biomaterials and, recently, photobioengineering. This work aimed to assess, through Raman spectroscopy, the level of bone mineralization using the intensities of the Raman peaks of both inorganic (~960, ~1,070, and 1,077 cm -1 ) and organic (~1,454 and ~1,666 cm -1 ) contents of bone tissue. Forty rats were divided into four groups each subdivided into two subgroups accord- ing to the time of sacrifice (15 and 30 days). Surgical bone defects were made on the femur of each animal with a trephine drill. On animals of group clot, the defect was filled only by blood clot, on group LED, the defect filled with the clot was further irradiated. On animals of groups biomaterial and LED + biomaterial, the defect was filled by biomaterial and the last one was further irradiated (λ850±10 nm, 150 mW, Φ ~ 0.5 cm 2 , 20 J/cm 2 -session, 140 J/cm 2 -treatment) at 48-h inter- vals and repeated for 2 weeks. At both 15th and 30th days following sacrifice, samples were taken and analyzed by Raman spectroscopy. At the end of the experimental time, the intensity of hydroxyapatite (HA) (~960 cm -1 ) were higher on group LED + biomaterial and the peaks of both organic content (~1,454 and ~1,666 cm -1 ) and transitional HA (~1,070 and ~1,077 cm -1 ) were lower on the same group. It is concluded that the use of LED phototherapy associated to biomaterial was effective in improving bone healing on bone defects as a result of the increasing deposition of HA mea- sured by Raman spectroscopy. Keywords Biomaterial . Bone repair . Hydroxyapatite . LED phototherapy Introduction Bone loss may be a result of several pathological conditions, trauma, or as consequence of surgical procedures. Many ap- proaches for the correction of bone defects have been advo- cated. Among them is the use of several types of grafts and membranes as well as the combination of both [1–7]. Of all of the biomaterials used to improve bone repair, hydroxyapatite (HA) is the most investigated one on both clinical and histo- logical grounds and it has been found to be effective on improving bone formation [1, 2, 5]. HA may be manufactured using different compositions and shapes. It may be used L. G. P. Soares : A. M. C. Marques : M. G. Guarda : J. M. S. Aciole : A. S. Andrade : A. L. B. Pinheiro (*) Center of Biophotonics, School of Dentistry, Federal University of Bahia, Av. Araújo Pinho, 62, Canela, Salvador, BA, Brazil 40110-150 e-mail: albp@ufba.br L. G. P. Soares e-mail: luizguilherme_@hotmail.com A. M. C. Marques e-mail: cidamarques77@hotmail.com M. G. Guarda e-mail: mileguarda@hotmail.com J. M. S. Aciole e-mail: jouber_aciole@hotmail.com A. S. Andrade e-mail: alinesilvaodonto@yahoo.com.br A. M. C. Marques : A. L. B. Pinheiro National Institute of Optics and Photonics, University of São Paulo, Physics Institute of São Carlos, São Carlos, SP, Brazil 13560-970 A. L. B. Pinheiro : L. Silveira Jr. Camilo Castelo Branco University, Núcleo do Parque Tecnológico de São José dos Campos:Rod, Presidente Dutra Km 139, Eugênio de Melo, São José dos Campos, SP 12247-004, Brazil L. Silveira Jr. e-mail: landulfo.silveira@gmail.com Lasers Med Sci DOI 10.1007/s10103-014-1601-9